1. |
- Sigvald, Roland, et al.
(författare)
-
Molecular identification of bloodmeals and species composition in Culicoides biting midges
- 2013
-
Ingår i: Medical and Veterinary Entomology. - : Wiley. - 0269-283X .- 1365-2915. ; 27, s. 104-112
-
Tidskriftsartikel (refereegranskat)abstract
- Investigations of host preferences in haematophagous insects, including Culicoides biting midges (Diptera: Ceratopogonidae), are critical in order to assess transmission routes of vector-borne diseases. In this study, we collected and morphologically identified 164 blood-engorged Culicoides females caught in both light traps and permanent 12-m high suction traps during 20082010 in Sweden. Molecular analysis of the mitochondrial cytochrome c oxidase subunit I (COI) gene in the biting midges was performed to verify species classification, discern phylogenetic relationships and uncover possible cryptic species. Bloodmeal analysis using universal vertebrate cytochrome b primers revealed a clear distinction in host selection between mammalophilic and ornithophilic Culicoides species. Host sequences found matches in horse (n = 59), sheep (n = 39), cattle (n = 26), Eurasian elk (n = 1) and 10 different bird species (n = 18). We identified 15 Culicoides species previously recorded in Scandinavia and four additional species haplotypes that were distinctly different from the described species. All ornithophilic individuals (n = 23) were caught exclusively in the suction traps, as were, interestingly, almost all mammalophilic species (n = 41), indicating that many biting midge species may be able to cover long distances after completing a bloodmeal. These results add new information on the composition of Culicoides species and their host preferences and their potential long-distance dispersal while blood-engorged.
|
|
2. |
- Alm Rosenblad, Magnus, 1957, et al.
(författare)
-
Detection of signal recognition particle (SRP) RNAs in the nuclear ribosomal internal transcribed spacer 1 (ITS1) of three lineages of ectomycorrhizal fungi (Agaricomycetes, Basidiomycota)
- 2016
-
Ingår i: MycoKeys. - : Pensoft Publishers. - 1314-4057 .- 1314-4049. ; 13, s. 21-33
-
Tidskriftsartikel (refereegranskat)abstract
- During a routine scan for Signal Recognition Particle (SRP) RNAs in eukaryotic sequences, we surprisingly found in silico evidence in GenBank for a 265-base long SRP RNA sequence in the ITS1 region of a total of 11 fully identified species in three ectomycorrhizal genera of the Basidiomycota (Fungi): Astraeus, Russula, and Lactarius. To rule out sequence artifacts, one specimen from a species indicated to have the SRP RNA-containing ITS region in each of these genera was ordered and re-sequenced. Sequences identical to the corresponding GenBank entries were recovered, or in the case of a non-original but conspecific specimen differed by three bases, showing that these species indeed have an SRP RNA sequence incorporated into their ITS1 region. Other than the ribosomal genes, this is the first known case of non-coding RNAs in the eukaryotic ITS region, and it may assist in the examination of other types of insertions in fungal genomes.
|
|
3. |
- Nilsson, R. Henrik, 1976, et al.
(författare)
-
Mycobiome diversity: high-throughput sequencing and identification of fungi.
- 2019
-
Ingår i: Nature reviews. Microbiology. - : Springer Science and Business Media LLC. - 1740-1534 .- 1740-1526. ; 17, s. 95-109
-
Forskningsöversikt (refereegranskat)abstract
- Fungi are major ecological players in both terrestrial and aquatic environments by cycling organic matter and channelling nutrients across trophic levels. High-throughput sequencing (HTS) studies of fungal communities are redrawing the map of the fungal kingdom by hinting at its enormous - and largely uncharted - taxonomic and functional diversity. However, HTS approaches come with a range of pitfalls and potential biases, cautioning against unwary application and interpretation of HTS technologies and results. In this Review, we provide an overview and practical recommendations for aspects of HTS studies ranging from sampling and laboratory practices to data processing and analysis. We also discuss upcoming trends and techniques in the field and summarize recent and noteworthy results from HTS studies targeting fungal communities and guilds. Our Review highlights the need for reproducibility and public data availability in the study of fungal communities. If the associated challenges and conceptual barriers are overcome, HTS offers immense possibilities in mycology and elsewhere.
|
|
4. |
- Unterseher, Martin, et al.
(författare)
-
Mycobiomes of sympatric Amorphophallus albispathus (Araceae) and Camellia sinensis (Theaceae) – a case study reveals clear tissue preferences and differences in diversity and composition
- 2018
-
Ingår i: Mycological Progress. - : Springer Science and Business Media LLC. - 1617-416X .- 1861-8952. ; 17:4, s. 489-500
-
Tidskriftsartikel (refereegranskat)abstract
- Multiple biotic and abiotic parameters influence the dynamics of individual fungal species and entire communities. Major drivers for tropical plant endophytes are undoubtedly seasonality, local habitat conditions and biogeography. However, host specialization and tissue preferences also contribute to the structuring of endophytic mycobiomes. To elucidate such specializations and preferences, we sampled two commercially important, unrelated plant species, Amorphophallus albispathus and Camellia sinensis (tea plant) simultaneously at close proximity. The mycobiomes of different tissue types were assessed with high-throughput amplicon sequencing of the internal transcribed spacer DNA region. Both plants hosted different fungal communities and varied in α- and β-diversity, despite their neighboring occurrence. However, the fungal assemblages of Amorphophallus leaflets shared taxa with the mycobiomes of tea leaves, thereby suggesting common driving forces for leaf-inhabiting fungi irrespective of host plant identity. The mycobiome composition and diversity of tea leaves was clearly driven by leaf age. We suggest that the very youngest tea leaves are colonized by stochastic processes, while mycobiomes of old leaves are rather similar as the result of progressive succession. The biodiversity of fungi associated with A. albispathus was characterized by a large number of unclassified OTUs (at genus and species level) and by tissue-specific composition.This study is the first cultivation-independent high-throughput assessment of fungal biodiversity of an Amorphophallus species, and additionally expands the knowledge base on fungi associated with tea plants.
|
|
5. |
- Gómez-Martínez, Daniela, et al.
(författare)
-
Phenotypic and transcriptomic acclimation of the green microalga Raphidocelis subcapitata to high environmental levels of the herbicide diflufenican
- 2023
-
Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 875
-
Tidskriftsartikel (refereegranskat)abstract
- Herbicide pollution poses a worldwide threat to plants and freshwater ecosystems. However, the understanding of how organisms develop tolerance to these chemicals and the associated trade-off expenses are largely unknown. This study aims to investigate the physiological and transcriptional mechanisms underlying the acclimation of the green microalgal model species Raphidocelis subcapitata (Selenastraceae) towards the herbicide diflufenican, and the fitness costs associated with tolerance development. Algae were exposed for 12 weeks (corresponding to 100 generations) to diflufenican at the two environmental concentrations 10 and 310 ng/L. The monitoring of growth, pigment composition, and photosynthetic performance throughout the experiment revealed an initial dose-dependent stress phase (week 1) with an EC50 of 397 ng/L, followed by a time-dependent recovery phase during weeks 2 to 4. After week 4, R. subcapitata was acclimated to diflufenican exposure with a similar growth rate, content of carotenoids, and photosynthetic performance as the unexposed control algae. This acclimation state of the algae was explored in terms of tolerance acquisition, changes in the fatty acids composition, diflufenican removal rate, cell size, and changes in mRNA gene expression profile, revealing potential fitness costs associated with acclimation, such as up-regulation of genes related to cell division, structure, morphology, and reduction of cell size. Overall, this study demonstrates that R. subcapitata can quickly acclimate to environmental but toxic levels of diflufenican; however, the acclimation is associated with trade-off expenses that result in smaller cell size.
|
|
6. |
- Airaud, M, et al.
(författare)
-
Biologie - Les manuels visuels pour la Licence
- 2018
-
Bok (övrigt vetenskapligt/konstnärligt)abstract
- En couleurs et très illustré, ce manuel a été conçu pour vous qui débutez un cursus scientifique universitaire. Il vous permettra d’acquérir les connaissances fondamentales en biologie, mais aussi la démarche et la rigueur scientifiques indispensables aux études supérieures. De multiples rubriques vous garantissent un apprentissage progressif et complet : un cours visuel avec de nombreux exemples concrets pour introduire et illustrer les notions et concepts clés ; des encadrés méthodologiques pour vous guider vers les bonnes pratiques et vous faire découvrir les grandes méthodes expérimentales ; des focus sur des applications, sujets de recherche ou thèmes d’actualité ; des repères historiques ; de nombreux QCM et exercices (tous corrigés) pour tester vos acquis et vous entraîner.
|
|
7. |
- Zhao, M., et al.
(författare)
-
Phylogenetic position of the Wallcreeper Tichodroma muraria
- 2016
-
Ingår i: Journal of Ornithology = Journal fur Ornithologie. - : Springer Science and Business Media LLC. - 0021-8375 .- 1439-0361. ; 157:3, s. 913-918
-
Tidskriftsartikel (refereegranskat)abstract
- The Wallcreeper Tichodroma muraria is usually placed in a monotypic family or subfamily within the superfamily Certhioidea, with assumed close relationships to Certhia (treecreepers), Sitta (nuthatches) and Salpornis (spotted creepers). Previous studies have suggested that Tichodroma is most closely related to Sitta, alternatively to Salpornis. We analysed the relationships of Tichodroma using two mitochondrial and five nuclear loci. The tree based on concatenated sequences strongly supported a sister relationship between Tichodroma and Sitta, as well as between Salpornis and Certhia. However, species tree analysis (MP-EST) was unable to resolve these relationships, and although the concatenation tree remains the best hypothesis, more data are needed to corroborate this. © 2016, Dt. Ornithologen-Gesellschaft e.V.
|
|
8. |
- Nilsson, R. Henrik, 1976, et al.
(författare)
-
The UNITE database for molecular identification of fungi: handling dark taxa and parallel taxonomic classifications.
- 2019
-
Ingår i: Nucleic acids research. - : Oxford University Press (OUP). - 1362-4962 .- 0305-1048. ; 47:D1
-
Tidskriftsartikel (refereegranskat)abstract
- UNITE (https://unite.ut.ee/) is a web-based database and sequence management environment for the molecular identification of fungi. It targets the formal fungal barcode-the nuclear ribosomal internal transcribed spacer(ITS) region-and offers all ∼1 000000 public fungal ITS sequences for reference. These are clustered into ∼459000 species hypotheses and assigned digital object identifiers (DOIs) to promote unambiguous reference across studies. In-house and web-based third-party sequence curation and annotation have resulted in more than 275000 improvements to the data over the past 15 years. UNITE serves as a data provider for a range of metabarcoding software pipelines and regularly exchanges data with all major fungal sequence databases and other community resources. Recent improvements include redesigned handling of unclassifiable species hypotheses, integration with the taxonomic backbone of the Global Biodiversity Information Facility, and support for an unlimited number of parallel taxonomic classification systems.
|
|
9. |
- Alström, Per, et al.
(författare)
-
A review of the recent advances in the systematics of the avian superfamily Sylvioidea
- 2013
-
Ingår i: Chinese Birds. - : Chinese Birds (Press). - 1674-7674. ; 4, s. 99-131
-
Tidskriftsartikel (refereegranskat)abstract
- The systematics of the avian superfamily Sylvioidea are reviewed, focusing on studies of relationships among families and within genera, more superficially on taxonomic studies at the species level. For the families Bernieridae and Phylloscopidae, new analyses based on already published sequence data are presented. Our understanding of relationships has been vastly improved in recent years due to a large number of molecular studies. However, the relationships among the different families remain largely obscured, probably mainly as a result of rapid divergence of the different primary lineages (families). Also, species level taxonomy has been much improved in recent years due to a large number of studies applying molecular markers and/or vocalizations and other life-history data. It seems likely that the number of species will continue to increase, as new groups are being studied with modern integrative methods.
|
|
10. |
- Alström, Per, et al.
(författare)
-
Dramatic niche shifts and morphological change in two insular bird species
- 2015
-
Ingår i: Royal Society Open Science. - : The Royal Society. - 2054-5703. ; 2
-
Tidskriftsartikel (refereegranskat)abstract
- Colonizations of islands are often associated with rapid morphological divergence. We present two previously unrecognized cases of dramatic morphological change and niche shifts in connection with colonization of tropical forest-covered islands. These evolutionary changes have concealed the fact that the passerine birds madanga, Madanga ruficollis, from Buru, Indonesia, and São Tomé shorttail, Amaurocichla bocagii, from São Tomé, Gulf of Guinea, are forest-adapted members of the family Motacillidae (pipits and wagtails). We show that Madanga has diverged mainly in plumage, which may be the result of selection for improved camouflage in its new arboreal niche, while selection pressures for other morphological changes have probably been weak owing to preadaptations for the novel niche. By contrast, we suggest that Amaurocichla's niche change has led to divergence in both structure and plumage.
|
|
11. |
- Alström, Per, et al.
(författare)
-
Integrative taxonomy of the Plain-backed Thrush (Zoothera mollissima) complex (Aves, Turdidae) reveals cryptic species, including a new species.
- 2016
-
Ingår i: Avian research. - : Elsevier BV. - 2053-7166. ; 7:1
-
Tidskriftsartikel (refereegranskat)abstract
- Background: The Plain-backed Thrush Zoothera mollissima breeds in the Himalayas and mountains of central China. It was long considered conspecific with the Long-tailed Thrush Zoothera dixoni, until these were shown to be broadly sympatric. Methods: We revise the Z. mollissima–Z. dixoni complex by integrating morphological, acoustic, genetic (two mito- chondrial and two nuclear markers), ecological and distributional datasets. Results: In earlier field observations, we noted two very different song types of“Plain-backed”Thrush segregated by breeding habitat and elevation. Further integrative analyses congruently identify three groups: an alpine breeder in the Himalayas and Sichuan, China (“Alpine Thrush”); a forest breeder in the eastern Himalayas and northwest Yunnan (at least), China (“Himalayan Forest Thrush”); and a forest breeder in central Sichuan (“Sichuan Forest Thrush”). Alpine and Himalayan Forest Thrushes are broadly sympatric, but segregated by habitat and altitude, and the same is prob- ably true also for Alpine and Sichuan Forest Thrushes. These three groups differ markedly in morphology and songs. In addition, DNA sequence data from three non-breeding specimens from Yunnan indicate that yet another lineage exists (“Yunnan Thrush”). However, we find no consistent morphological differences from Alpine Thrush, and its breed- ing range is unknown. Molecular phylogenetic analyses suggest that all four groups diverged at least a few million years ago, and identify Alpine Thrush and the putative “Yunnan Thrush” as sisters, and the two forest taxa as sisters. Cytochrome b divergences among the four Z. mollissima sensu lato (s.l.) clades are similar to those between any of them and Z. dixoni, and exceed that between the two congeneric outgroup species. We lectotypify the name Oreocin- cla rostrata Hodgson, 1845 with the Z. mollissima sensu stricto (s.s.) specimen long considered its type. No available name unambiguously pertains to the Himalayan Forest Thrush. Conclusions: The Plain-backed Thrush Z. mollissima s.l. comprises at least three species: Alpine Thrush Z. mollissima s.s., with a widespread alpine breeding distribution; Sichuan Forest Thrush Z. griseiceps, breeding in central Sichuan forests; and Himalayan Forest Thrush, breeding in the eastern Himalayas and northwest Yunnan (at least), which is described herein as a new species. “Yunnan Thrush” requires further study.
|
|
12. |
- Halwachs, Bettina, et al.
(författare)
-
Critical Issues in mycobiota analysis
- 2017
-
Ingår i: Frontiers in Microbiology. - : Frontiers Media SA. - 1664-302X. ; 8
-
Tidskriftsartikel (refereegranskat)abstract
- Fungi constitute an important part of the human microbiota and they play a significant role for health and disease development. Advancements made in the culture-independent analysis of microbial communities have broadened our understanding of the mycobiota, however, microbiota analysis tools have been mainly developed for bacteria (e.g., targeting the 16S rRNA gene) and they often fall short if applied to fungal marker-gene based investigations (i.e., internal transcribed spacers, ITS). In the current paper we discuss all major steps of a fungal amplicon analysis starting with DNA extraction from specimens up to bioinformatics analyses of next-generation sequencing data. Specific points are discussed at each step and special emphasis is placed on the bioinformatics challenges emerging during operational taxonomic unit (OTU) picking, a critical step in mycobiota analysis. By using an in silico ITS1 mock community we demonstrate that standard analysis pipelines fall short if used with default settings showing erroneous fungal community representations. We highlight that switching OTU picking to a closed reference approach greatly enhances performance. Finally, recommendations are given on how to perform ITS based mycobiota analysis with the currently available measures.
|
|
13. |
|
|
14. |
- Olsson, Urban, 1954, et al.
(författare)
-
The Lanius excubitor (Aves, Passeriformes) conundrum – Taxonomic dilemma when molecular and non-molecular data tell different stories.
- 2010
-
Ingår i: Molecular Phylogenetics and Evolution. - : Elsevier BV. - 1055-7903 .- 1095-9513. ; 55:2, s. 347-357
-
Tidskriftsartikel (refereegranskat)abstract
- The phylogeny of 18 taxa in the Lanius excubitor complex, and the related species L. sphenocercus, L. ludovicianus and L. somalicus, was estimated based on the mitochondrial cytochrome b gene and the non-coding D-loop (in total ∼1.3 kb). According to the mitochondrial gene tree, Lanius excubitor s.l. is non-monophyletic, with some of its subspecies being more closely related to L. sphenocercus, L. ludovicianus, and L. somalicus. Also the division of the L. excubitor complex into a northern (L. excubitor) and a southern (L. meridionalis) species, as has been proposed based on morphological and ecological similarity and geographical distributions, is not compatible with the mitochondrial tree. Overall, genetic divergences among the ingroup taxa are small, indicating a recent radiation. A tree based on the nuclear ornithine decarboxylase (ODC) introns 6–7 is unresolved with respect to the ingroup, but provides strong support for a clade containing the Lanius excubitor complex, L. sphenocercus, L. ludovicianus and L. somalicus. We discuss the incongruence between the current taxonomy and the mitochondrial gene tree, and conclude that based on the latter the Lanius excubitor complex may be treated as at least six species, L. borealis, L. elegans, L. excubitor, L. lahtora, L. meridionalis, and L. uncinatus, but that other taxonomic treatments are also possible. However, uncertainty regarding to which extent the mitochondrial gene tree reflects the species phylogeny prevents us from recommending taxonomic change without further investigation. This study highlights the possible danger of relying on a single molecular marker, such as mitochondrial DNA, in taxonomic revisions and phylogenetic inference
|
|
15. |
- Subhash, Santhilal, 1987, et al.
(författare)
-
Sperm Originated Chromatin Imprints and LincRNAs in Organismal Development and Cancer
- 2020
-
Ingår i: iScience. - : Elsevier BV. - 2589-0042. ; 23:6
-
Tidskriftsartikel (refereegranskat)abstract
- Importance of sperm-derived transcripts and chromatin imprints in organismal development is poorly investigated. Here using an integrative approach, we show that human sperm transcripts are equally important as oocyte. Sperm-specific and sperm-oocyte common transcripts carry distinct chromatin structures at their promoters correlating with corresponding transcript levels in sperm. Interestingly, sperm-specific H3K4me3 patterns at the lincRNA promoters are not maintained in the germ layers and somatic tissues. However, bivalent chromatin at the sperm-specific protein-coding gene promoters is maintained throughout the development. Sperm-specific transcripts reach their peak expression during zygotic genome activation, whereas sperm-oocyte common transcripts are present during early preimplantation development but decline at the onset of zygotic genome activation. Additionally, there is an inverse correlation between sperm-specific and sperm-oocyte lincRNAs throughout the development. Sperm-lincRNAs also show aberrant activation in tumors. Overall, our observations indicate that sperm transcripts carrying chromatin imprints may play an important role in human development and cancer.
|
|
16. |
- Bengtsson-Palme, Johan, 1985, et al.
(författare)
-
Metaxa2 Database Builder: enabling taxonomic identification from metagenomic or metabarcoding data using any genetic marker
- 2018
-
Ingår i: Bioinformatics (Oxford, England). - : Oxford University Press (OUP). - 1367-4811 .- 1367-4803. ; 34:23, s. 4027-4033
-
Tidskriftsartikel (refereegranskat)abstract
- Correct taxonomic identification of DNA sequences is central to studies of biodiversity using both shotgun metagenomic and metabarcoding approaches. However, no genetic marker gives sufficient performance across all the biological kingdoms, hampering studies of taxonomic diversity in many groups of organisms. This has led to the adoption of a range of genetic markers for DNA metabarcoding. While many taxonomic classification software tools can be re-trained on these genetic markers, they are often designed with assumptions that impair their utility on genes other than the SSU and LSU rRNA. Here, we present an update to Metaxa2 that enables the use of any genetic marker for taxonomic classification of metagenome and amplicon sequence data.We evaluated the Metaxa2 Database Builder on eleven commonly used barcoding regions and found that while there are wide differences in performance between different genetic markers, our software performs satisfactorily provided that the input taxonomy and sequence data are of high quality.Freely available on the web as part of the Metaxa2 package at http://microbiology.se/software/metaxa2/.Supplementary data are available at Bioinformatics online.
|
|
17. |
- Borchert, Erik, et al.
(författare)
-
Deciphering a Marine Bone-Degrading Microbiome Reveals a Complex Community Effort
- 2021
-
Ingår i: mSystems. - 2379-5077 .- 2379-5077. ; 6:1
-
Tidskriftsartikel (refereegranskat)abstract
- The marine bone biome is a complex assemblage of macro- and microor- ganisms; however, the enzymatic repertoire to access bone-derived nutrients remains unknown. The bone matrix is a composite material made up mainly of organic colla- gen and inorganic hydroxyapatite. We conducted field experiments to study microbial assemblages that can use organic bone components as nutrient source. Bovine and turkey bones were deposited at 69 m depth in a Norwegian fjord (Byfjorden, Bergen). Metagenomic sequence analysis was used to assess the functional potential of micro- bial assemblages from bone surface and the bone-eating worm Osedax mucofloris, which is a frequent colonizer of whale falls and known to degrade bone. The bone microbiome displayed a surprising taxonomic diversity revealed by the examination of 59 high-quality metagenome-assembled genomes from at least 23 bacterial families. Over 700 genes encoding enzymes from 12 relevant enzymatic families pertaining to collagenases, peptidases, and glycosidases putatively involved in bone degradation were identified. Metagenome-assembled genomes (MAGs) of the class Bacteroidia con- tained the most diverse gene repertoires. We postulate that demineralization of inor- ganic bone components is achieved by a timely succession of a closed sulfur biogeo- chemical cycle between sulfur-oxidizing and sulfur-reducing bacteria, causing a drop in pH and subsequent enzymatic processing of organic components in the bone sur- face communities. An unusually large and novel collagen utilization gene cluster was retrieved from one genome belonging to the gammaproteobacterial genus Colwellia. IMPORTANCE Bones are an underexploited, yet potentially profitable feedstock for biotechnological advances and value chains, due to the sheer amounts of residues produced by the modern meat and poultry processing industry. In this metagenomic study, we decipher the microbial pathways and enzymes that we postulate to be involved in bone degradation in the marine environment. We here demonstrate the interplay between different bacterial community members, each supplying different enzymatic functions with the potential to cover an array of reactions relating to the degradation of bone matrix components. We identify and describe a novel gene cluster for collagen utilization, which is a key function in this unique environment. We propose that the interplay between the different microbial taxa is necessary to achieve the complex task of bone degradation in the marine environment.
|
|
18. |
- Drennan, Regan, et al.
(författare)
-
Annelid Fauna of the Prince Gustav Channel, a Previously Ice-Covered Seaway on the Northeastern Antarctic Peninsula
- 2021
-
Ingår i: Frontiers in Marine Science. - : Frontiers Media SA. - 2296-7745. ; 7
-
Tidskriftsartikel (refereegranskat)abstract
- The Prince Gustav Channel is a narrow seaway located in the western Weddell Sea on the northeastern-most tip of the Antarctic Peninsula. The channel is notable for both its deep (>1200 m) basins, and a dynamic glacial history that most recently includes the break-up of the Prince Gustav Ice Shelf, which covered the southern portion of the channel until its collapse in 1995. However, the channel remains mostly unsampled, with very little known about its benthic biology. We present a preliminary account of the benthic annelid fauna of the Prince Gustav Channel in addition to samples from Duse Bay, a sheltered, glacier-influenced embayment in the northwestern portion of the channel. Samples were collected using an Agassiz Trawl, targeting megafaunal and large macrofaunal sized animals at depths ranging between 200–1200 m; the seafloor and associated fauna were also documented in situ using a Shallow Underwater Camera System (SUCS). Sample sites varied in terms of depth, substrate type, and current regime, and communities were locally variable across sites in terms of richness, abundance, and both taxonomic and functional composition. The most diverse family included the motile predator/scavenger Polynoidae, with 105 individuals in at least 12 morphospecies, primarily from a single site. This study provides first insights into diverse and spatially heterogeneous benthic communities in a dynamic habitat with continuing glacial influence, filling sampling gaps in a poorly studied region of the Southern Ocean at direct risk from climate change. These specimens will also be utilized in future molecular investigations, both in terms of describing the genetic biodiversity of this site and as part of wider phylogeographic and population genetic analyses assessing the connectivity, evolutionary origins, and demographic history of annelid fauna in the region.
|
|
19. |
- Caputo, Andrea, 1988-
(författare)
-
Genomic and morphological diversity of marine planktonic diatom-diazotroph associations : a continuum of integration and diversification through geological time
- 2019
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Symbioses between eukaryotes and nitrogen (N2)-fixing cyanobacteria (or diazotrophs) are quite common in the plankton community. A few genera of diatoms (Bacillariophyceae) such as Rhizosolenia, Hemiaulus and Chaetoceros are well known to form symbioses with the heterocystous diazotrophic cyanobacteria Richelia intracellularis and Calothrix rhizosoleniae. The latter are also called diatom-diazotroph associations, or DDAs. Up to now, the prokaryotic partners have been morphologically and genetically characterized, and the phylogenetic reconstruction of the well conserved nifH gene (encodes for the nitrogenase enzyme) placed the symbionts in 3 clusters based on their host-specificity, i.e. het-1 (Rhizosolenia-R. intracellularis), het-2 (Hemiaulus-R. intracellularis), and het-3 (Chaetoceros-C- rhizosoleniae). Conversely, the diatom-hosts, major representative of the phytoplankton community and crucial contributors to the carbon (C) biogeochemical cycle, have been understudied.The first aim of this thesis was to genetically and morphologically characterize the diatom-hosts, and to reconstruct the evolutionary background of the partnerships and the symbiont integration in the host. The molecular-clock analysis reconstruction showed the ancient appearance of the DDAs, and the traits characterizing the ancestors. In addition, diatom-hosts bearing internal symbionts (with more eroded draft genomes) appeared earlier than diatom-hosts with external symbionts. Finally a blast survey highlighted a broader distribution of the DDAs than expected.The second aim of this thesis was to compare genetic and physiological characteristics of the DDAs symbionts with the other eukaryote-diazotroph symbiosis, i.e. prymnesiophyte-UCYN-A (or Candidatus Atelocyanobacterium thalassa). The genome comparison highlighted more genes for transporters in het-3 (external symbiont) and in the UCYN-A based symbiosis, suggesting that symbiont location might be relevant also for metabolic exchanges and interactions with the host and/or environment. Moreover, a summary of methodological biases that brought to an underestimation of the DDAs is reported.The third aim of this thesis was to determine the distribution of the DDAs in the South Pacific Ocean using a quantitative polymerase chain reaction (qPCR) approach and to outline the environmental drivers of such distribution. Among the het-groups, het-1 was the most abundant/detected and co-occurred with the other 2 symbiotic strains, all responding similarly to the influence of abiotic factors, such as temperature and salinity (positive and negative correlation, respectively). Globally, Trichodesmium dominated the qPCR detections, followed by UCYN-B. UCYN-A phylotypes (A-1, A-2) were detected without their proposed hosts, for which new oligonucleotides were designed. The latter suggested a facultative symbiosis. Finally, microscopy observations of the het-groups highlighted a discrepancy with the qPCR counts (i.e. the former were several order of magnitudes lower), leading to the idea of developing a new approach to quantify the DDAs. The fourth aim of this thesis was to develop highly specific in situ hybridization assays (CARD-FISH) to determine the presence of alternative life-stages and/or free-living partners. The new assays were applied to samples collected in the South China Sea and compared with abundance estimates from qPCR assays for the 3 symbiotic strains. Free-living cells were indeed detected along the transect, mainly at deeper depths. Free-living symbionts had two morphotypes: trichomes and single-cells. The latter were interpreted as temporary life-stages. Consistent co-occurrence of the 3 het-groups was also found in the SCS and application of a SEM model predicted positive interactions between the het groups. We interpreted the positive interaction as absence of intra-specific competition, and consistent with the previous study, temperature and salinity were predicted as major drivers of the DDAs distribution.
|
|
20. |
- Kulma, Katarzyna, et al.
(författare)
-
Malaria-infected female collared flycatchers (Ficedula albicollis) do not pay the cost of late breeding
- 2014
-
Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 9:1, s. e85822-
-
Tidskriftsartikel (refereegranskat)abstract
- Life-history theory predicts that the trade-off between parasite defense and other costly traits such as reproduction may be most evident when resources are scarce. The strength of selection that parasites inflict on their host may therefore vary across environmental conditions. Collared flycatchers (Ficedula albicollis) breeding on the Swedish island Oland experience a seasonal decline in their preferred food resource, which opens the possibility to test the strength of life-history trade-offs across environmental conditions. We used nested-PCR and quantitative-PCR protocols to investigate the association of Haemosporidia infection with reproductive performance of collared flycatcher females in relation to a seasonal change in the external environment. We show that despite no difference in mean onset of breeding, infected females produced relatively more of their fledglings late in the season. This pattern was also upheld when considering only the most common malaria lineage (hPHSIB1), however there was no apparent link between the reproductive output and the intensity of infection. Infected females produced heavier-than-average fledglings with higher-than-expected recruitment success late in the season. This reversal of the typical seasonal trend in reproductive output compensated them for lower fledging and recruitment rates compared to uninfected birds earlier in the season. Thus, despite different seasonal patterns of reproductive performance the overall number of recruits was the same for infected versus uninfected birds. A possible explanation for our results is that infected females breed in a different microhabitat where food availability is higher late in the season but also is the risk of infection. Thus, our results suggest that another trade-off than the one we aimed to test is more important for explaining variation in reproductive performance in this natural population: female flycatchers appear to face a trade-off between the risk of infection and reproductive success late in the season.
|
|
21. |
- Hooper, D. M., et al.
(författare)
-
The Rusty-tailed Flycatcher (Muscicapa ruficauda; Ayes: Muscicapidae) is a member of the genus Ficedula
- 2016
-
Ingår i: Molecular Phylogenetics and Evolution. - : Elsevier BV. - 1055-7903 .- 1095-9513. ; 102, s. 56-61
-
Tidskriftsartikel (refereegranskat)abstract
- The phylogenetic relationships of the avian family Muscicapidae (Old World chats and flycatchers) have historically been enigmatic and remain an active area of study. Widespread instances of non-monophyly resulting from misleading morphological and behavioral similarities have merited numerous taxonomic revisions to the group. Here we report one such instance with regard to the Rusty-tailed Flycatcher Muscicapa ruficauda, which has recently been placed in the newly proposed monotypic genus Ripleyia, due to inferred sister relationship to the genus Muscicapa and related genera (Voelker et al., 2016a). This name was later replaced by Ripleyornis, as it was realized that Ripleyia is a junior homonym of a genus of Mollusca (Voelker et al., 2016b). Using a Bayesian phylogenetic assessment of the Muscicapidae with near-complete taxon sampling of the genus Ficedula for five loci, along with an acoustic comparison of M. ruficauda to a subset of other flycatcher species, we show that this species should be reassigned to the genus Ficedula and accordingly that the names Ripleyia and Ripleyornis are both junior synonyms of Ficedula. (C) 2016 Elsevier Inc. All rights reserved.
|
|
22. |
- Li, Xinlei, et al.
(författare)
-
Shaped by uneven Pleistocene climate: mitochondrial phylogeographic pattern and population history of White Wagtail Motacilla alba (Aves: Passeriformes).
- 2016
-
Ingår i: Journal of Avian Biology. - : Wiley. - 0908-8857 .- 1600-048X. ; 47, s. 263-274
-
Tidskriftsartikel (refereegranskat)abstract
- We studied the phylogeography and population history of the white wagtail Motacilla alba, which has a vast breeding range, covering areas with different Pleistocene climatic histories. The mitochondrial NADH dehydrogenase subunit II gene (ND2) and Control Region (CR) were analyzed for 273 individuals from 45 localities. Our data comprised all nine subspecies of white wagtail. Four primary clades were inferred (M, N, SW and SE), with indications of M. grandis being nested within M. alba. The oldest split was between two haplotypes from the endemic Moroccan M. a. subpersonata (clade M) and the others, at 0.63–0.96 Mya; other divergences were at 0.31–0.38 Mya. The entire differentiation falls within the part of the Pleistocene characterized by Milankovitch cycles of large amplitudes and durations. Clade N was distributed across the northern Palearctic; clade SW in southwestern Asia plus the British Isles and was predicted by Ecological niche models (ENMs) to occur also in central and south Europe; and clade SE was distributed in central and east Asia. e deep divergence within M. a. subpersonata may reflect retention of ancestral haplotypes. Regional differences in historical climates have had different impacts on different populations: clade N expanded after the last glacial maximum (LGM), whereas milder Pleistocene climate of east Asia allowed clade SE a longer expansion time (since MIS 5); clade SW expanded over a similarly long time as clade SE, which is untypical for European species. ENMs supported these conclusions in that the northern part of the Eurasian continent was unsuitable during the LGM, whereas southern parts remained suitable. e recent divergences and poor structure in the mitochondrial tree contrasts strongly with the pronounced, well defined phenotypical differentiation, indicating extremely fast plumage divergence.
|
|
23. |
- Olsson, Urban, 1954, et al.
(författare)
-
Mitochondrial phylogeny of the Eurasian/African reed warbler complex (Acrocephalus, Aves). Disagreement between morphological and molecular evidence and cryptic divergence: A case for resurrecting Calamoherpe ambigua Brehm 1857
- 2016
-
Ingår i: Molecular Phylogenetics and Evolution. - : Elsevier BV. - 1055-7903 .- 1095-9513. ; 102, s. 30-44
-
Tidskriftsartikel (refereegranskat)abstract
- A tree based on the mitochondrial cyt b gene for 278 samples from throughout the range of the Eurasian Reed Warbler Acrocephalus scirpaceus - African Reed Warbler A. baeticatus complex shows well supported geographically structured divergence for eight distinct lineages. The phylogenetic structuring together with the clarification of priority, provided by sequence data from seven type specimens, suggests that both taxonomy and distribution boundaries are in need of revision. The Iberian and Moroccan populations form a well-supported Glade, and we propose that these are treated as taxonomically distinct, under the name ambiguus (Brehm, 1857). We propose that the names scirpaceus, fuscus, avicenniae, ambiguus, minor, cinnamomeus, hallae and baeticatus are used for the well supported clades in the complex, which we recommend to treat as one polytypic species, A. scirpaceus, pending studies of gene flow and assortative mating in the contact zones. (C) 2016 Elsevier Inc. All rights reserved.
|
|
24. |
- Wintersparv Stervander, Martin, et al.
(författare)
-
Multiple instances of paraphyletic species and cryptic taxa revealed by mitochondrial and nuclear RAD data for Calandrella larks (Aves: Alaudidae)
- 2016
-
Ingår i: Molecular Phylogenetics and Evolution. - : Elsevier BV. - 1055-7903 .- 1095-9513. ; 102, s. 233-245
-
Tidskriftsartikel (refereegranskat)abstract
- The avian genus Calandrella (larks) was recently suggested to be non-monophyletic, and was divided into two genera, of which Calandrella sensu stricto comprises 4-5 species in Eurasia and Africa. We analysed mitochondrial cytochrome b (cytb) and nuclear Restriction-site Associated DNA (RAD) sequences from all species, and for cytb we studied 21 of the 22 recognised subspecies, with the aim to clarify the phylogenetic relationships within the genus and to compare large-scale nuclear sequence patterns with a widely used mitochondrial marker. Cytb indicated deep splits among the currently recognised species, although it failed to support the interrelationships among most of these. It also revealed unexpected deep divergences within C. brachydactyla, C. blanfordi/C erlangeri, C. cinerea, and C. acutirostris. It also suggested that both C. brachydactyla and C. blanfordi, as presently circumscribed, are paraphyletic. In contrast, most of the many subspecies of C brachydactyla and C. cinerea were unsupported by cytb, although two populations of C. cinerea were found to be genetically distinct. The RAD data corroborated the cytb tree (for the smaller number of taxa analysed) and recovered strongly supported interspecific relationships. However, coalescence analyses of the RAD data, analysed in SNAPP both with and without an outgroup, received equally strong support for two conflicting topologies. We suggest that the tree rooted with an outgroup - which is not recommended for SNAPP - is more trustworthy, and suggest that the reliability of analyses performed without any outgroup species should be thoroughly evaluated. We also demonstrate that degraded museum samples can be phylogenetically informative in RAD analyses following careful bioinformatic treatment. We note that the genus Calandrella is in need of taxonomic revision. (C) 2016 Elsevier Inc. All rights reserved.
|
|
25. |
- De Chiara, Matteo, et al.
(författare)
-
Domestication reprogrammed the budding yeast life cycle
- 2022
-
Ingår i: Nature Ecology & Evolution. - : Springer Science and Business Media LLC. - 2397-334X .- 2397-334X. ; 6
-
Tidskriftsartikel (refereegranskat)abstract
- Domestication of plants and animals is the foundation for feeding the world human population but can profoundly alter the biology of the domesticated species. Here we investigated the effect of domestication on one of our prime model organisms, the yeast Saccharomyces cerevisiae, at a species-wide level. We tracked the capacity for sexual and asexual reproduction and the chronological life span across a global collection of 1,011 genome-sequenced yeast isolates and found a remarkable dichotomy between domesticated and wild strains. Domestication had systematically enhanced fermentative and reduced respiratory asexual growth, altered the tolerance to many stresses and abolished or impaired the sexual life cycle. The chronological life span remained largely unaffected by domestication and was instead dictated by clade-specific evolution. We traced the genetic origins of the yeast domestication syndrome using genome-wide association analysis and genetic engineering and disclosed causative effects of aneuploidy, gene presence/absence variations, copy number variations and single-nucleotide polymorphisms. Overall, we propose domestication to be the most dramatic event in budding yeast evolution, raising questions about how much domestication has distorted our understanding of the natural biology of this key model species.
|
|
26. |
- Liu, B. Y., et al.
(författare)
-
Explosive radiation and spatial expansion across the cold environments of the Old World in an avian family
- 2017
-
Ingår i: Ecology and Evolution. - : Wiley. - 2045-7758. ; 7:16, s. 6346-6357
-
Tidskriftsartikel (refereegranskat)abstract
- Our objective was to elucidate the biogeography and speciation patterns in an entire avian family, which shows a complex pattern of overlapping and nonoverlapping geographical distributions, and much variation in plumage, but less in size and structure. We estimated the phylogeny and divergence times for all of the world's species of Prunella based on multiple genetic loci, and analyzed morphometric divergence and biogeographical history. The common ancestor of Prunella was present in the Sino-Himalayan Mountains or these mountains and Central Asia-Mongolia more than 9 million years ago (mya), but a burst of speciations took place during the mid-Pliocene to early Pleistocene. The relationships among the six primary lineages resulting from that differentiation are unresolved, probably because of the rapid radiation. A general increase in sympatry with increasing time since divergence is evident. With one exception, species in clades younger than c. 3.7 my are allopatric. Species that are widely sympatric, including the most recently diverged (2.4 mya) sympatric sisters, are generally more divergent in size/structure than allo-/parapatric close relatives. The distributional pattern and inferred ages suggest divergence in allopatry and substantial waiting time until secondary contact, likely due to competitive exclusion. All sympatrically breeding species are ecologically segregated, as suggested by differences in size/structure and habitat. Colonizations of new areas were facilitated during glacialperiods, followed by fragmentation during interglacials-contrary to the usual view that glacial periods resulted mainly in fragmentations.
|
|
27. |
- Alström, Per, et al.
(författare)
-
Discovery of a relict lineage and monotypic family of passerine birds.
- 2014
-
Ingår i: Biology Letters. - : The Royal Society. - 1744-9561 .- 1744-957X. ; 10:3
-
Tidskriftsartikel (refereegranskat)abstract
- Analysis of one of the most comprehensive datasets to date of the largest passerine bird clade, Passerida, identified 10 primary well-supported lineages corresponding to Sylvioidea, Muscicapoidea, Certhioidea, Passeroidea, the ‘bombycillids’ (here proposed to be recognized as Bombycilloidea), Paridae/Remizidae (proposed to be recognized as Paroidea), Stenostiridae, Hyliotidae, Regulidae (proposed to be recognized as Reguloidea) and spotted wren-babbler Spelaeornis formosus. The latter was found on a single branch in a strongly supported clade with Muscicapoidea, Certhioidea and Bombycilloidea, although the relationships among these were unresolved. We conclude that the spotted wren-babbler represents a relict basal lineage within Passerida with no close extant relatives, and we support the already used name Elachura formosa and propose the new family name Elachuridae for this single species.
|
|
28. |
- Alström, Per, et al.
(författare)
-
New insights into family relationships within the avian superfamily Sylvioidea (Passeriformes) based on seven molecular markers
- 2012
-
Ingår i: BMC Evolutionary Biology. - : Springer Science and Business Media LLC. - 1471-2148. ; 12, s. 1-12
-
Tidskriftsartikel (refereegranskat)abstract
- Background: The circumscription of the avian superfamily Sylvioidea is a matter of long ongoing debate. While the overall inclusiveness has now been mostly agreed on and 20 families recognised, the phylogenetic relationships among the families are largely unknown. We here present a phylogenetic hypothesis for Sylvioidea based on one mitochondrial and six nuclear markers, in total ~6.3 kbp, for 79 ingroup species representing all currently recognised families and some species with uncertain affinities, making this the most comprehensive analysis of this taxon. Results: The resolution, especially of the deeper nodes, is much improved compared to previous studies. However, many relationships among families remain uncertain and are in need of verification. Most families themselves are very well supported based on the total data set and also by indels. Our data do not support the inclusion of Hylia in Cettiidae, but do not strongly reject a close relationship with Cettiidae either. The genera Scotocerca and Erythrocercus are closely related to Cettiidae, but separated by relatively long internodes. The families Paridae, Remizidae and Stenostiridae clustered among the outgroup taxa and not within Sylvioidea. Conclusions: Although the phylogenetic position of Hylia is uncertain, we tentatively support the recognition of the family Hyliidae Bannerman, 1923 for this genus and Pholidornis. We propose new family names for the genera Scotocerca and Erythrocercus, Scotocercidae and Erythrocercidae, respectively, rather than including these in Cettiidae, and we formally propose the name Macrosphenidae, which has been in informal use for some time. We recommend that Paridae, Remizidae and Stenostiridae are not included in Sylvioidea. We also briefly discuss the problems of providing a morphological diagnosis when proposing a new family-group name (or genus-group name) based on a clade.
|
|
29. |
- Bourlat, Sarah, et al.
(författare)
-
Feeding ecology of Xenoturbella bocki (phylum Xenoturbellida) revealed by genetic barcoding
- 2008
-
Ingår i: Molecular Ecology Resources. - 1755-098X. ; 8, s. 18-22
-
Tidskriftsartikel (refereegranskat)abstract
- The benthic marine worm Xenoturbella is frequently contaminated with molluscan DNA, which had earlier caused confusion resulting in a suggested bivalve relationship. In order to find the source of the contaminant, we have used molluscan sequences derived from Xenoturbella and compared them to barcodes obtained from several individuals of the nonmicroscopic molluscs sharing the same environment as Xenoturbella. Using cytochrome oxidase 1, we found the contaminating sequences to be 98% similar to the bivalve Ennucula tenuis. Using the highly variable D1-D2 region of the large ribosomal subunit in Xenoturbella, we found three distinct species of contaminating molluscs, one of which is 99% similar to the bivalve Abra nitida, one of the most abundant bivalves in the Gullmarsfjord where Xenoturbella was found, and another 99% similar to the bivalve Nucula sulcata. These data clearly show that Xenoturbella only contains molluscan DNA originating from bivalves living in the same environment, refuting former hypotheses of a bivalve relationship. In addition, these data suggest that Xenoturbella feeds specifically on bivalve prey from multiple species, possibly in the form of eggs and larvae.
|
|
30. |
- Green, Leon, et al.
(författare)
-
Ancestral Sperm Ecotypes Reveal Multiple Invasions of a Non-Native Fish in Northern Europe
- 2021
-
Ingår i: Cells. - : MDPI AG. - 2073-4409. ; 10:7
-
Tidskriftsartikel (refereegranskat)abstract
- For externally fertilising organisms in the aquatic environment, the abiotic fertilisation medium can be a strong selecting force. Among bony fishes, sperm are adapted to function in a narrow salinity range. A notable exception is the family Gobiidae, where several species reproduce across a wide salinity range. The family also contains several wide-spread invasive species. To better understand how these fishes tolerate such varying conditions, we measured sperm performance in relation to salinity from a freshwater and a brackish population within their ancestral Ponto-Caspian region of the round goby, Neogobius melanostomus. These two ancestral populations were then compared to nine additional invaded sites across northern Europe, both in terms of their sperm traits and by using genomic SNP markers. Our results show clear patterns of ancestral adaptations to freshwater and brackish salinities in their sperm performance. Population genomic analyses show that the ancestral ecotypes have generally established themselves in environments that fit their sperm adaptations. Sites close to ports with intense shipping show that both outbreeding and admixture can affect the sperm performance of a population in a given salinity. Rapid adaptation to local conditions is also supported at some sites. Historical and contemporary evolution in the traits of the round goby sperm cells is tightly linked to the population and seascape genomics as well as biogeographic processes in these invasive fishes. Since the risk of a population establishing in an area is related to the genotype by environment match, port connectivity and the ancestry of the round goby population can likely be useful for predicting the species spread.
|
|
31. |
- Olsson, Urban, 1954, et al.
(författare)
-
Molecular evidence suggests that the enigmatic Sulawesi endemic Geomalia heinrichi belongs in the genus Zoothera (Turdidae, Aves).
- 2013
-
Ingår i: Chinese Birds. - : Chinese Birds (Press). - 1674-7674. ; 4:2, s. 155-160
-
Tidskriftsartikel (refereegranskat)abstract
- The taxonomic status of the Sulawesi endemic Geomalia heinrichi has long been debated, and it has variously been treated as a babbler (Timaliidae) or a turdid (Turdidae). We estimated the phylogeny of 43 taxa in the family Turdidae based on the mitochondrial cytochrome b gene and the nuclear myoglobin intron 2 and ornithine decarboxylase introns 6–7. Geomalia heinrichi was shown to be part of the Zoothera clade with high support. We propose that Geomalia is transferred to Zoothera under the name Zoothera heinrichi.
|
|
32. |
- Olsson, Urban, 1954, et al.
(författare)
-
Systematic revision of the avian family Cisticolidae based on a multi-locus phylogeny of all genera
- 2013
-
Ingår i: Molecular Phylogenetics and Evolution. - : Elsevier BV. - 1055-7903 .- 1095-9513. ; 66:3, s. 790-799
-
Tidskriftsartikel (refereegranskat)abstract
- The avian taxon Cisticolidae includes c. 110 species which are distributed throughout the tropical and subtropical parts of the Old World. We estimated the phylogeny of 47 species representing all genera assumed to be part of Cisticolidae based on sequence data from two mitochondrial and two nuclear markers, in total 3495 bp. Bayesian inference and maximum likelihood analyses resulted in a generally well-supported phylogeny which clarified the position of several previously poorly known taxa. The placement of Drymocichla, Malcorus, Micromacronus, Oreophilais, Phragmacia, Phyllolais, Poliolais and Urorhipis in Cisticolidae is corroborated, whereas Rhopophilus and Scotocerca are removed from Cisticolidae. Urorhipis and Heliolais are placed in the genus Prinia whereas Prinia burnesii is shown to be part of Timaliidae, and is placed in the genus Laticilla. Although not recovered by all single loci independently, four major clades were identified within Cisticolidae, and one of these is here described as a new taxon (Neomixinae).
|
|
33. |
- Janzon, Anders, 1978, et al.
(författare)
-
Exploring the microbial resistome in river sediments exposed to extraordinary high levels of antibiotics
- 2010
-
Ingår i: 35th FEBS Congress: Molecules of Life.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The rapid development and propagation of antibiotic resistance in pathogenic and opportunistic bacteria is a major threat to public health worldwide. The phenomenon has been widely studied in the clinical setting, but comparatively little is known about the prevalence and diversity of antibiotic resistance in communities of environmental bacteria, often referred to as the environmental resistome. As the external environment may function as a reservoir of resistance genes to human pathogens, we are interested in how environmental bacteria are affected by antibiotic pollution. We have previously isolated microbial DNA from river sediments taken up- and downstream from a water treatment plant that processes waste water from several pharmaceutical plants producing antibiotics. In a previous study, we used deep sequencing to identify unprecedented frequencies of known resistance genes to several classes of antibiotics in these samples. In this study, we aim to functionally characterize the resistome in a more open and exploratory way by screening genomic DNA libraries transformed into sensitive hosts. To generate the libraries, several experimental strategies were explored, including mechanical shearing and enzymatic digestion of the isolated DNA followed by blunt- or sticky end cloning into different plasmids, subsequently transformed into sensitive E. coli. Pros and cons of the different strategies will be discussed along with preliminary results of the screening against selected antibiotics.
|
|
34. |
- Alström, Per, et al.
(författare)
-
Integrative taxonomy of the Russet Bush Warbler Locustella mandelli complex reveals a new species from central China
- 2015
-
Ingår i: Avian Research. - : Elsevier BV. - 2053-7166. ; 6:9
-
Tidskriftsartikel (refereegranskat)abstract
- Background: The Russet Bush Warbler Locustella (previously Bradypterus) mandelli complex occurs in mountains in the eastern Himalayas, southern China, Vietnam, the Philippines, and Indonesia. The taxonomy has been debated, with one (L. seebohmi) to four (L. seebohmi, L. mandelli, L. montis and L. timorensis) species having been recognised. Methods: We used an integrative approach, incorporating analyses of morphology, vocalizations and a molecular marker, to re-evaluate species limits in the L. mandelli complex. Results: We found that central Chinese L. mandelli differed from those from India through northern Southeast Asia to southeast China in plumage, morphometrics and song. All were easily classified by song, and (wing + culmen)/tail ratio overlapped only marginally. Both groups were reciprocally monophyletic in a mitochondrial cytochrome b (cytb) gene tree, with a mean divergence of 1.0 +/- 0.2%. They were sympatric and mostly altitudinally segregated in the breeding season in southern Sichuan province. We found that the Mt Victoria (western Myanmar) population differed vocally from other L. mandelli, but no specimens are available. Taiwan Bush Warbler L. alishanensis was sister to the L. mandelli complex, with the most divergent song. Plumage, vocal and cytb evidence supported the distinctness of the south Vietnamese L. mandelli idonea. The Timor Bush Warbler L. timorensis, Javan Bush Warbler L. montis and Benguet Bush Warbler L. seebohmi differed distinctly in plumage, but among-population song variation in L. montis exceeded the differences between some populations of these taxa, and mean pairwise cytb divergences were only 0.5-0.9%. We also found that some L. montis populations differed morphologically. Conclusions: We conclude that the central Chinese population of Russet Bush Warbler represents a new species, which we describe herein, breeding at mid elevations in Sichuan, Shaanxi, Hubei, Hunan and Guizhou provinces. The taxonomic status of the other allopatric populations is less clear. However, as they differ to a degree comparable with that of the sympatric L. mandelli and the new species, we elevate L. idonea to species status, and retain L. seebohmi and L. montis as separate species, the latter with timorensis as a subspecies. Further research should focus on different populations of L. montis and the Mt Victoria population of L. mandelli.
|
|
35. |
- Dong, L., et al.
(författare)
-
Taxonomy of the Narcissus Flycatcher Ficedula narcissina complex: an integrative approach using morphological, bioacoustic and multilocus DNA data
- 2015
-
Ingår i: Ibis. - : Wiley. - 0019-1019 .- 1474-919X. ; 157:2, s. 312-325
-
Tidskriftsartikel (refereegranskat)abstract
- The taxonomy of the Narcissus Flycatcher Ficedula narcissina-Yellow-rumped Flycatcher Ficedula zanthopygia complex from East Asia has long been debated. Most authors recognize two species: F.narcissina, with the subspecies narcissina (most of Japan and Sakhalin Island), owstoni (south Japanese islands) and elisae (northeast China) and F.zanthopygia (monotypic), although species status has been proposed for elisae and sometimes for owstoni. Here, we revise the taxonomy of this complex based on an integrative approach utilizing morphology, songs and mitochondrial and nuclear DNA for all taxa. All taxa were diagnosably different in plumage, and there were also structural differences among them, although the northernmost populations of owstoni (sometimes recognized as jakuschima and shonis) were somewhat intermediate in plumage, structure and male plumage maturation between southern populations of owstoni and narcissina. All taxa had different songs, and a discriminant function analysis of four song variables correctly classified 100% of all songs. A strongly supported phylogeny was recovered based on three mitochondrial genes and three nuclear introns (total of 3543bp), revealing a sister relationship between F.zanthopygia and the other taxa, between F.n.narcissina and F.n.owstoni, and between F.n.elisae and F.n.narcissina+F.n.owstoni. The corrected COI distances among the three F.narcissina subspecies ranged from 2.8% (narcissina-owstoni) to 8.2% (narcissina-elisae). We suggest that the congruent differences in multiple independent traits and the deep genetic divergences among the four taxa in the F.narcissina-F.zanthopygia complex support treatment of all of these taxa as separate species. However, we acknowledge the paucity of data for F.owstoni and recommend further studies of this taxon. We suggest listing both F.elisae and F.owstoni, which have small and fragmented populations, as globally threatened.
|
|
36. |
- Jarvis, Erich D., et al.
(författare)
-
Whole-genome analyses resolve early branches in the tree of life of modern birds
- 2014
-
Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 346:6215, s. 1320-1331
-
Tidskriftsartikel (refereegranskat)abstract
- To better determine the history of modern birds, we performed a genome-scale phylogenetic analysis of 48 species representing all orders of Neoaves using phylogenomic methods created to handle genome-scale data. We recovered a highly resolved tree that confirms previously controversial sister or close relationships. We identified the first divergence in Neoaves, two groups we named Passerea and Columbea, representing independent lineages of diverse and convergently evolved land and water bird species. Among Passerea, we infer the common ancestor of core landbirds to have been an apex predator and confirm independent gains of vocal learning. Among Columbea, we identify pigeons and flamingoes as belonging to sister clades. Even with whole genomes, some of the earliest branches in Neoaves proved challenging to resolve, which was best explained by massive protein-coding sequence convergence and high levels of incomplete lineage sorting that occurred during a rapid radiation after the Cretaceous-Paleogene mass extinction event about 66 million years ago.
|
|
37. |
- Lindner, Daniel L., et al.
(författare)
-
Employing 454 amplicon pyrosequencing to reveal intragenomic divergence in the internal transcribed spacer rDNA region in fungi
- 2013
-
Ingår i: Ecology and Evolution. - : Wiley. - 2045-7758. ; 3:6, s. 1751-1764
-
Tidskriftsartikel (refereegranskat)abstract
- The rDNA internal transcribed spacer (ITS) region has been accepted as a DNA barcoding marker for fungi and is widely used in phylogenetic studies; however, intragenomic ITS variability has been observed in a broad range of taxa, including prokaryotes, plants, animals, and fungi, and this variability has the potential to inflate species richness estimates in molecular investigations of environmental samples. In this study 454 amplicon pyrosequencing of the ITS1 region was applied to 99 phylogenetically diverse axenic single-spore cultures of fungi (Dikarya: Ascomycota and Basidiomycota) to investigate levels of intragenomic variation. Three species (one Basidiomycota and two Ascomycota), in addition to a positive control species known to contain ITS paralogs, displayed levels of molecular variation indicative of intragenomic variation; taxon inflation due to presumed intragenomic variation was ≈9%. Intragenomic variability in the ITS region appears to be widespread but relatively rare in fungi (≈3–5% of species investigated in this study), suggesting this problem may have minor impacts on species richness estimates relative to PCR and/or pyrosequencing errors. Our results indicate that 454 amplicon pyrosequencing represents a powerful tool for investigating levels of ITS intragenomic variability across taxa, which may be valuable for better understanding the fundamental mechanisms underlying concerted evolution of repetitive DNA regions.
|
|
38. |
- Price, T. D., et al.
(författare)
-
Niche filling slows the diversification of Himalayan songbirds
- 2014
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 509:7499
-
Tidskriftsartikel (refereegranskat)abstract
- Speciation generally involves a three-step process-range expansion, range fragmentation and the development of reproductive isolation between spatially separated populations(1,2). Speciation relies on cycling through these three steps and each may limit the rate at which new species form(1,3). We estimate phylogenetic relationships among all Himalayan songbirds to ask whether the development of reproductive isolation and ecological competition, both factors that limit range expansions(4), set an ultimate limit on speciation. Based on a phylogeny for all 358 species distributed along the eastern elevational gradient, here we show that body size and shape differences evolved early in the radiation, with the elevational band occupied by a species evolving later. These results are consistent with competition for niche space limiting species accumulation(5). Even the elevation dimension seems to be approaching ecological saturation, because the closest relatives both inside the assemblage and elsewhere in the Himalayas are on average separated by more than five million years, which is longer than it generally takes for reproductive isolation to be completed(2,3,6); also, elevational distributions are well explained by resource availability, notably the abundance of arthropods, and not by differences in diversification rates in different elevational zones. Our results imply that speciation rate is ultimately set by niche filling(that is, ecological competition for resources), rather than by the rate of acquisition of reproductive isolation.
|
|
39. |
- Zhang, Ruiying, et al.
(författare)
-
Comparative phylogeography of two widespread magpies : importance of habitat preference and breeding behavior on genetic structure in China.
- 2012
-
Ingår i: Molecular Phylogenetics and Evolution. - : Elsevier BV. - 1055-7903 .- 1095-9513. ; 65:2, s. 562-72
-
Tidskriftsartikel (refereegranskat)abstract
- Historical geological events and climatic changes are believed to have played important roles in shaping the current distribution of species. However, sympatric species may have responded in different ways to such climatic fluctuations. Here we compared genetic structures of two corvid species, the Azure-winged Magpie Cyanopica cyanus and the Eurasian Magpie Pica pica, both widespread but with different habitat dependence and some aspects of breeding behavior. Three mitochondrial genes and two nuclear introns were used to examine their co-distributed populations in East China and the Iberian Peninsula. Both species showed deep divergences between these two regions that were dated to the late Pliocene/early Pleistocene. In the East Chinese clade of C. cyanus, populations were subdivided between Northeast China and Central China, probably since the early to mid-Pleistocene, and the Central subclade showed a significant pattern of isolation by distance. In contrast, no genetic structure was found in the East China populations of P. pica. We suggest that the different patterns in the two species are at least partly explained by ecological differences between them, especially in habitat preference and perhaps also breeding behavior. These dissimilarities in life history traits might have affected the dispersal and survival abilities of these two species differently during environmental fluctuations.
|
|
40. |
- Zhang, Z., et al.
(författare)
-
Unexpected divergence and lack of divergence revealed in continental Asian Cyornis flycatchers (Aves: Muscicapidae)
- 2016
-
Ingår i: Molecular Phylogenetics and Evolution. - : Elsevier BV. - 1055-7903 .- 1095-9513. ; 94:Part: A, s. 232-241
-
Tidskriftsartikel (refereegranskat)abstract
- The flycatcher genus Cyornis (Aves: Muscicapidae) comprises 25 species with Oriental distributions. Their relationships are poorly known. We analyzed the phylogenetic relationships of 70 individuals from 12 species and several subspecies of Cyornis based on three mitochondrial genes and five nuclear introns, with special focus on Chinese and Vietnamese populations of the monotypic C. hainanus and polytypic C. rubeculoides. We found no support for inclusion of C. concretus in Cyornis. Deep divergences were observed among different subspecies of C. banyumas and C. rubeculoides. C. rubeculoides glaucicomans was also shown to have a highly distinctive song, and we propose that it is treated as a distinctive Chinese endemic species, C. glaucicomans. In contrast, the south Vietnamese C. rubeculoides klossi, which has a disjunct distribution from the other subspecies of C. rubeculoides, along with a recently discovered population in Guangdong Province (China) with several plumage reminiscent of C. r. klossi, were indistinguishable in all loci analyzed from the phenotypically markedly different C. hainanus. More research is needed to elucidate the reasons for this unexpected pattern. © 2015 Elsevier Inc.
|
|
41. |
- Delling, Bo, 1964-, et al.
(författare)
-
Genetic signs of multiple colonization events in Baltic ciscoes with radiation into sympatric spring- and autumnspawners confined to early postglacial arrival
- 2014
-
Ingår i: Ecology and Evolution. - : John Wiley & Sons. - 2045-7758. ; 4:22, s. 4346-4360
-
Tidskriftsartikel (refereegranskat)abstract
- Presence of sympatric populations may reflect local diversification or secondary contact of already distinct forms. The Baltic cisco (Coregonus albula) normally spawns in late autumn, but in a few lakes in Northern Europe sympatric autumn and spring- or winter-spawners have been described. So far, the evolutionary relationships and taxonomic status of these main life history forms have remained largely unclear. With microsatellites and mtDNA sequences, we analyzed extant and extinct spring- and autumn-spawners from a total of 23 Swedish localities, including sympatric populations. Published sequences from Baltic ciscoes in Germany and Finland, and Coregonus sardinella from North America were also included together with novel mtDNA sequences from Siberian C. sardinella. A clear genetic structure within Sweden was found that included two population assemblages markedly differentiated at microsatellites and apparently fixed for mtDNA haplotypes from two distinct clades. All sympatric Swedish populations belonged to the same assemblage, suggesting parallel evolution of spring-spawning rather than secondary contact. The pattern observed further suggests that postglacial immigration to Northern Europe occurred from at least two different refugia. Previous results showing that mtDNA in Baltic cisco is paraphyletic with respect to North American C. sardinella were confirmed. However, the inclusion of Siberian C. sardinella revealed a more complicated pattern, as these novel haplotypes were found within one of the two main C. albula clades and were clearly distinct from those in North American C. sardinella. The evolutionary history of Northern Hemisphere ciscoes thus seems to be more complex than previously recognized.
|
|
42. |
- Hagenblad, Jenny, et al.
(författare)
-
Low genetic diversity despite multipleintroductions of the invasive plant species Impatiens glandulifera in Europe
- 2015
-
Ingår i: BMC Genetics. - : Springer Science and Business Media LLC. - 1471-2156. ; 16:103
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Invasive species can be a major threat to native biodiversity and the number of invasive plant speciesis increasing across the globe. Population genetic studies of invasive species can provide key insights into theirinvasion history and ensuing evolution, but also for their control. Here we genetically characterise populations ofImpatiens glandulifera, an invasive plant in Europe that can have a major impact on native plant communities. Wecompared populations from the species’ native range in Kashmir, India, to those in its invaded range, along alatitudinal gradient in Europe. For comparison, the results from 39 other studies of genetic diversity in invasivespecies were collated.Results: Our results suggest that I. glandulifera was established in the wild in Europe at least twice, from an areaoutside of our Kashmir study area. Our results further revealed that the genetic diversity in invasive populations ofI. glandulifera is unusually low compared to native populations, in particular when compared to other invasivespecies. Genetic drift rather than mutation seems to have played a role in differentiating populations in Europe. Wefind evidence of limitations to local gene flow after introduction to Europe, but somewhat less restrictions in thenative range. I. glandulifera populations with significant inbreeding were only found in the species’ native rangeand invasive species in general showed no increase in inbreeding upon leaving their native ranges. In Europe wedetect cases of migration between distantly located populations. Human activities therefore seem to, at leastpartially, have facilitated not only introductions, but also further spread of I. glandulifera across Europe.Conclusions: Although multiple introductions will facilitate the retention of genetic diversity in invasive ranges,widespread invasive species can remain genetically relatively invariant also after multiple introductions. Phenotypicplasticity may therefore be an important component of the successful spread of Impatiens glandulifera across Europe.
|
|
43. |
|
|
44. |
- Kulma, Katarzyna, et al.
(författare)
-
Malaria infections reinforce competitive asymmetry between two Ficedula flycatchers in a recent contact zone
- 2013
-
Ingår i: Molecular Ecology. - : Wiley. - 0962-1083 .- 1365-294X. ; 22:17, s. 4591-4601
-
Tidskriftsartikel (refereegranskat)abstract
- Parasites may influence the outcome of interspecific competition between closely related host species through lower parasite virulence in the host with which they share the longer evolutionary history. We tested this idea by comparing the prevalence of avian malaria (Haemosporidia) lineages and their association with survival in pied and collared flycatchers (Ficedula hypoleuca and F. albicollis) breeding in a recent contact zone on the Swedish island of Oland. A nested PCR protocol amplifying haemosporidian fragments of mtDNA was used to screen the presence of malaria lineages in 1048 blood samples collected during 6 years. Competitively inferior pied flycatchers had a higher prevalence of blood parasites, including the lineages that were shared between the two flycatcher species. Multistate mark-recapture models revealed a lower survival of infected versus uninfected female pied flycatchers, while no such effects were detected in male pied flycatchers or in collared flycatchers of either sex. Our results show that a comparatively new host, the collared flycatcher, appears to be less susceptible to a local northern European malarial lineage where the collared flycatchers have recently expanded their distribution. Pied flycatchers experience strong reproductive interference from collared flycatchers, and the additional impact of species-specific blood parasite effects adds to this competitive exclusion. These results support the idea that parasites can strongly influence the outcome of interspecific competition between closely related host species, but that the invading species need not necessarily be more susceptible to local parasites.
|
|
45. |
- Mozzachiodi, S., et al.
(författare)
-
Aborting meiosis allows recombination in sterile diploid yeast hybrids
- 2021
-
Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 12:1
-
Tidskriftsartikel (refereegranskat)abstract
- Hybrids are often considered evolutionary dead ends because they do not generate viable offspring. Here, the authors show that sterile yeast hybrids generate genetic diversity through meiotic-like recombination by aborting meiosis and return to asexual growth. Hybrids between diverged lineages contain novel genetic combinations but an impaired meiosis often makes them evolutionary dead ends. Here, we explore to what extent an aborted meiosis followed by a return-to-growth (RTG) promotes recombination across a panel of 20 Saccharomyces cerevisiae and S. paradoxus diploid hybrids with different genomic structures and levels of sterility. Genome analyses of 275 clones reveal that RTG promotes recombination and generates extensive regions of loss-of-heterozygosity in sterile hybrids with either a defective meiosis or a heavily rearranged karyotype, whereas RTG recombination is reduced by high sequence divergence between parental subgenomes. The RTG recombination preferentially arises in regions with low local heterozygosity and near meiotic recombination hotspots. The loss-of-heterozygosity has a profound impact on sexual and asexual fitness, and enables genetic mapping of phenotypic differences in sterile lineages where linkage analysis would fail. We propose that RTG gives sterile yeast hybrids access to a natural route for genome recombination and adaptation.
|
|
46. |
- Stenberg, Simon, et al.
(författare)
-
Control of mitochondrial superoxide production includes programmed mtDNA deletion and restoration
- 2020
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Deletion of mitochondrial DNA in eukaryotes is mainly attributed to rare accidental events associated with mitochondrial replication or repair of double-strand breaks. We report the discovery that yeast cells arrest harmful intramitochondrial superoxide production by shutting down respiration through genetically controlled deletion of mitochondrial oxidative phosphorylation genes. We show that the regulatory circuitry underlying this editing critically involves the antioxidant enzyme superoxide dismutase 2 and two-way mitochondrial-nuclear communication. While mitochondrial DNA homeostasis is rapidly restored after cessation of a short-term superoxide stress, long-term stress causes maladaptive persistence of the deletion process, leading to complete annihilation of the cellular pool of intact mitochondrial genomes and irrevocable loss of respiratory ability. Our results may therefore be of etiological as well as therapeutic importance with regard to age-related mitochondrial impairment and disease.One-Sentence SummaryGenetically controlled editing of mitochondrial DNA is an integral part of the yeast’s defenses against oxidative damage.
|
|
47. |
- Ödeen, Anders, et al.
(författare)
-
Multiple shifts between violet and ultraviolet vision in a family of passerine birds with associated changes in plumage coloration
- 2012
-
Ingår i: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 279:1732, s. 1269-1276
-
Tidskriftsartikel (refereegranskat)abstract
- Colour vision in diurnal birds falls into two discrete classes, signified by the spectral sensitivity of the violet- (VS) or ultraviolet-sensitive (UVS) short wavelength-sensitive type 1 (SWS1) single cone. Shifts between sensitivity classes are rare; three or four are believed to have happened in the course of avian evolution, one forming UVS higher passerines. Such shifts probably affect the expression of shortwave-dominated plumage signals. We have used genomic DNA sequencing to determine VS or UVS affinity in fairy-wrens and allies, Maluridae, a large passerine family basal to the known UVS taxa. We have also spectrophotometrically analysed male plumage coloration as perceived by the VS and UVS vision systems. Contrary to any other investigated avian genus, Malurus (fairy-wrens) contains species with amino acid residues typical of either VS or UVS cone opsins. Three bowerbird species (Ptilonorhynchidae) sequenced for outgroup comparison carry VS opsin genes. Phylogenetic reconstructions render one UVS gain followed by one or more losses as the most plausible evolutionary scenario. The evolution of avian ultraviolet sensitivity is hence more complex, as a single shift no longer explains its distribution in Passeriformes. Character correlation analysis proposes that UVS vision is associated with shortwave-reflecting plumage, which is widespread in Maluridae.
|
|
48. |
- Spottiswoode, C. N., et al.
(författare)
-
Rediscovery of a long-lost lark reveals the conspecificity of endangered Heteromirafra populations in the Horn of Africa
- 2013
-
Ingår i: Journal of Ornithology. - : Springer Science and Business Media LLC. - 0021-8375 .- 2193-7192 .- 2193-7206. ; 154:3, s. 813-825
-
Tidskriftsartikel (refereegranskat)abstract
- The African lark genus Heteromirafra is thought to consist of three threatened species inhabiting mid-altitude grasslands, one in South Africa and two in the Horn of Africa. One of the latter, Archer's Lark H. archeri of Somaliland, has not been seen with certainty since 1922. We surveyed its type locality as well as a nearby area of grassland east of Jijiga in adjacent north-eastern Ethiopia, where sightings of Heteromirafra larks have recently been made. First, we used a combination of morphological and molecular evidence to show that these recent sightings refer to the same taxon as Archer's Lark. Second, we used a combination of morphological, molecular and vocal evidence to show that these populations are conspecific with the Liben (Sidamo) Lark H. sidamoensis of southern Ethiopia, but that the Horn of Africa populations are highly distinct from Rudd's Lark H. ruddi of South Africa. Third, we suggest that the extent and quality of their habitat in north-eastern Ethiopia is small and poor, and that the type locality of Archer's Lark in Somaliland has been completely transformed. Taken together, these results imply that there is a single species of Heteromirafra in the Horn of Africa (for which the scientific name H. archeri has priority, and which we suggest retains the English name Liben Lark), consisting of two tiny populations separated by 590 km of apparently unsuitable habitats. Environmental niche models suggest that there are no environmentally similar locations elsewhere within the region. Despite the discovery of a second population, the Liben Lark remains a highly threatened species in urgent need of conservation intervention to avert the extinction of both of its populations.
|
|
49. |
- Alström, Per, et al.
(författare)
-
Multilocus phylogeny of the avian family Alaudidae (larks) reveals complex morphological evolution, non-monophyletic genera and hidden species diversity
- 2013
-
Ingår i: Molecular Phylogenetics and Evolution. - : Elsevier BV. - 1055-7903 .- 1095-9513. ; 69:3, s. 1043-1056
-
Tidskriftsartikel (refereegranskat)abstract
- The Alaudidae (larks) is a large family of songbirds in the superfamily Sylvioidea. Larks are cosmopolitan, although species-level diversity is by far largest in Africa, followed by Eurasia, whereas Australasia and the New World have only one species each. The present study is the first comprehensive phylogeny of the Alaudidae. It includes 83.5% of all species and representatives from all recognised genera, and was based on two mitochondrial and three nuclear loci (in total 6.4 kbp, although not all loci were available for all species). In addition, a larger sample, comprising several subspecies of some polytypic species was analysed for one of the mitochondrial loci. There was generally good agreement in trees inferred from different loci, although some strongly supported incongruences were noted. The tree based on the concatenated multilocus data was overall well resolved and well supported by the data. We stress the importance of performing single gene as well as combined data analyses, as the latter may obscure significant incongruence behind strong nodal support values. The multilocus tree revealed many unpredicted relationships, including some non-monophyletic genera (Calandrella, Mirafra, Melanocorypha, Spizocorys). The tree based on the extended mitochondrial data set revealed several unexpected deep divergences between taxa presently treated as conspecific (e.g. within Ammomanes cinctura, Ammomanes deserti, Calandrella brachydactyla, Eremophila alpestris), as well as some shallow splits between currently recognised species (e.g. Certhilauda brevirostris-C semitorquata-C curvirostris; Calendulauda barlowi-C. erythrochlamys; Mirafra cantillans-M. javanica). Based on our results, we propose a revised generic classification, and comment on some species limits. We also comment on the extraordinary morphological adaptability in larks, which has resulted in numerous examples of parallel evolution (e.g. in Melanocorypha mongolica and Alauda leucoptera [both usually placed in Melanocorypha]; Ammomanopsis grayi and Ammomanes cinctura/deserti [former traditionally placed in Ammomanes]; Chersophilus duponti and Certhilauda spp.; Eremopterix hova [usually placed in Mirafra] and several Mirafra spp.), as well as both highly conserved plumages (e.g. within Mirafra) and strongly divergent lineages (e.g. Eremopterix hova vs. other Eremopterix spp.; Calandrella cinerea complex vs. Eremophila spp.; Eremalauda dunni vs. Chersophilus duponti; Melanocorypha mongolica and male M. yeltoniensis vs. other Melanocoupha spp. and female M. yeltoniensis). Sexual plumage dimorphism has evolved multiple times. Few groups of birds show the same level of disagreement between taxonomy based on morphology and phylogenetic relationships as inferred from DNA sequences. (C) 2013 Elsevier Inc. All rights reserved.
|
|
50. |
- Bélteky, Johan
(författare)
-
Chicken domestication : Effects of tameness on brain gene expression and DNA methylation
- 2016
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Domestication greatly increases phenotypic variation in a short time span, with selection for a single phenotype and a plethora of associated phenotypic changes as an outcome of the process. The domestication process influences the underlying genomic architecture of a species, and the success and speed of the process is likely influenced by it. The main aims of my thesis was to study how domestication affects the brain of chickens: specifically changes in morphology, gene expression, and DNA methylation. Differences in gene expression and DNA methylation between White Leghorn and Red Junglefowl chickens were mapped, and inheritance of these patterns were quantified, indicating a faithful transmission of breed-specific epigenetic markers. Selection on the behavioral trait fearfulness, generated high and low fearful lines of Red Junglefowl. Both the parental population and the fifth selected generation were used for the analyses in this thesis. One experiment studied morphological changes in the brain and other vital organs, and found that relative total brain size increased in high fearful birds, as a consequence of an increase in cerebral hemisphere size in high fearful birds and not in low fearful birds. Also, the relative heart, liver, spleen and testis size increased in high fearful birds, indicating correlated morphological changes with selection for fearfulness. Two additional experiments examined differential gene expression in the hypothalamus and the anterior cerebral hemisphere. The hypothalamus differed in expression of genes with reproductive and immunological functions, whilst the cerebral hemisphere differed in expression of genes related to social behaviors and neurological functions especially those upregulated in low fearful birds. These results indicate the occurrence of tissue- and species-specific changes in gene expression as overlap with other domestication events were nearly nonexistent. A fourth experiment sought to associate the change in fear levels and gene expression differences with DNA methylation. Chromosomal regions with differential DNA methylation between high and low fearful birds were identified, and genes in these regions had annotated functions relevant to phenotypic differences between the selection lines. This thesis is the first to study the genetic alterations of domestication using the wild ancestor of an already domesticated species to repeat the domestication process selecting against fear of humans. The findings corroborate results from previous comparisons of wild and domestic animals, and further support the theory that rigorous selection for a behavioral trait can cause a cascade of genetic and epigenetic changes facilitating the domestication of a population.
|
|