| 1. |
- Bertrand, Yann, et al.
(författare)
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First Dating of a Recombination Event in Mammalian Tick-borne Flaviviruses
- 2012
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Ingår i: PLoS ONE. - San Francisco : Public Library of Science (PLoS). - 1932-6203. ; 7:2
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Tidskriftsartikel (refereegranskat)abstract
- The mammalian tick-borne flavivirus group (MTBFG) contains viruses associated with important human and animal diseases such as encephalitis and hemorrhagic fever. In contrast to mosquito-borne flaviviruses where recombination events are frequent, the evolutionary dynamic within the MTBFG was believed to be essentially clonal. This assumption was challenged with the recent report of several homologous recombinations within the Tick-borne encephalitis virus (TBEV). We performed a thorough analysis of publicly available genomes in this group and found no compelling evidence for the previously identified recombinations. However, our results show for the first time that demonstrable recombination (i.e., with large statistical support and strong phylogenetic evidences) has occurred in the MTBFG, more specifically within the Louping ill virus lineage. Putative parents, recombinant strains and breakpoints were further tested for statistical significance using phylogenetic methods. We investigated the time of divergence between the recombinant and parental strains in a Bayesian framework. The recombination was estimated to have occurred during a window of 282 to 76 years before the present. By unravelling the temporal setting of the event, we adduce hypotheses about the ecological conditions that could account for the observed recombination.
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| 2. |
- Rasmusson, Lina M., et al.
(författare)
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Sensitivity of photosynthesis to warming in two similar species of the aquatic angiosperm ruppia from tropical and temperate habitats
- 2021
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Ingår i: Sustainability. - : MDPI AG. - 2071-1050. ; 13:16
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Tidskriftsartikel (refereegranskat)abstract
- Climate change-related events, such as marine heatwaves, are increasing seawater temperatures, thereby putting pressure on marine biota. The cosmopolitan distribution and significant contribution to marine primary production by the genus Ruppia makes them interesting organisms to study thermal tolerance and local adaptation. In this study, we investigated the photosynthetic responses in Ruppia to the predicted future warming in two contrasting bioregions, temperate Sweden and tropical Thailand. Through DNA barcoding, specimens were determined to Ruppia cirrhosa for Sweden and Ruppia maritima for Thailand. Photosynthetic responses were assessed using pulse amplitude-modulated fluorometry, firstly in short time incubations at 18, 23, 28, and 33◦ C in the Swedish set-up and 28, 33, 38, and 43◦ C in the Thai set-up. Subsequent experiments were conducted to compare the short time effects to longer, five-day incubations in 28◦ C for Swedish plants and 40◦ C for Thai plants. Swedish R. cirrhosa displayed minor response, while Thai R. maritima was more sensitive to both direct and prolonged temperature stress with a drastic decrease in the photosynthetic parameters leading to mortality. The results indicate that in predicted warming scenarios, Swedish R. cirrhosa may sustain an efficient photosynthesis and potentially outcompete more heat-sensitive species. However, populations of the similar R. maritima in tropical environments may suffer a decline as their productivity will be highly reduced.
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| 3. |
- Crespo, Ana, et al.
(författare)
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Phylogenetic generic classification of parmelioid lichens (Parmeliaceae,Ascomycota) based on molecular, morphological and chemical evidence.
- 2010
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Ingår i: Taxon. - : John Wiley & Sons. - 0040-0262 .- 1996-8175. ; 59:6, s. 1735-1753
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Tidskriftsartikel (refereegranskat)abstract
- Parmelioid lichens are a diverse and ubiquitous group of foliose lichens. Generic delimitation in parmelioid lichens has been in a state of flux since the late 1960s with the segregation of the large, heterogeneous genus Parmelia into numerous smaller genera. Recent molecular phylogenetic studies have demonstrated that some of these new genera were monophyletic, some were not, and others, previously believed to be unrelated, fell within single monophyletic groups, indicating the need for a revision of the generic delimitations. This study aims to give an overview of current knowledge of the major clades of all parmelioid lichens. For this, we assembled a dataset of 762 specimens, including 31 of 33 currently accepted parmelioid genera (and 63 of 84 accepted genera of Parmeliaceae). We performed maximum likelihood and Bayesian analyses of combined datasets including two, three and four loci. Based on these phylogenies and the correlation of morphological and chemical characters that characterize monophyletic groups, we accept 27 genera within nine main clades. We re-circumscribe several genera and reduce Parmelaria to synonymy with Parmotrema. Emodomelanelia Divakar & A. Crespo is described as a new genus (type: E. masonii). Nipponoparmelia (Kurok.) K.H. Moon, Y. Ohmura & Kashiw. ex A. Crespo & al. is elevated to generic rank and 15 new combinations are proposed (in the genera Flavoparmelia, Parmotrema, Myelochroa, Melanelixia and Nipponoparmelia). A short discussion of the accepted genera is provided and remaining challenges and areas requiring additional taxon sampling are identified.
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| 4. |
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| 5. |
- Arup, Ulf, et al.
(författare)
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Professor Ingvar Kärnfelt - a birthday tribute
- 2009
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Ingår i: The Lichenologist. - Cambridge : Cambridge University Press. - 0024-2829 .- 1096-1135. ; 41:5, s. 453-456
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- On 19 July 2009 Ingvar Kärnefelt celebrated his 65th birthday. This could have meant that we, his former students, would be celebrating him in his retirement from his position as head of the Biological Museums at Lund University. We are grateful that this is not the case, as Ingvar will carry on, probably for at least one or two more years. Instead, we celebrate Ingvar because he is the main reason for all of us having studied lichenology in Lund. This special issue of The Lichenologist is dedicated to him as a birthday tribute in honour of his long and fruitful lichenological career. The main authors of all the papers in this issue are former students of Ingvar. For several of us he has not only acted as supervisor but later also as the director of the Botanical Museum where we meet him in our daily work.
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| 6. |
- Divakar, Pradeep K., et al.
(författare)
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Evolution of complex symbiotic relationships in a morphologically derived family of lichen-forming fungi
- 2015
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Ingår i: New Phytologist. - : Wiley. - 0028-646X .- 1469-8137. ; 208:4, s. 1217-1226
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Tidskriftsartikel (refereegranskat)abstract
- We studied the evolutionary history of the Parmeliaceae (Lecanoromycetes, Ascomycota), one of the largest families of lichen-forming fungi with complex and variable morphologies, also including several lichenicolous fungi. We assembled a six-locus data set including nuclear, mitochondrial and low-copy protein-coding genes from 293 operational taxonomic units (OTUs). The lichenicolous lifestyle originated independently three times in lichenized ancestors within Parmeliaceae, and a new generic name is introduced for one of these fungi. In all cases, the independent origins occurred c. 24 million yr ago. Further, we show that the Paleocene, Eocene and Oligocene were key periods when diversification of major lineages within Parmeliaceae occurred, with subsequent radiations occurring primarily during the Oligocene and Miocene. Our phylogenetic hypothesis supports the independent origin of lichenicolous fungi associated with climatic shifts at the Oligocene-Miocene boundary. Moreover, diversification bursts at different times may be crucial factors driving the diversification of Parmeliaceae. Additionally, our study provides novel insight into evolutionary relationships in this large and diverse family of lichen-forming ascomycetes.
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| 7. |
- Janson, Sven, et al.
(författare)
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Population genetic structure of crucian carp (Carassius carassius) in man-made ponds and wild populations in Sweden
- 2015
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Ingår i: Aquaculture International. - : Springer Science and Business Media LLC. - 0967-6120 .- 1573-143X. ; 23:1, s. 359-368
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Although once popular prior to the last century, the aquaculture of crucian carp Carassius carassius (L. 1758) in Sweden gradually fell from favour. This is the first genetic comparison of crucian carp from historic man-made ponds in the Scandinavian Peninsula. The aim was to identify old populations without admixture and to compare the relationship of pond populations from different provinces in Sweden. In total, nine microsatellite loci from 234 individuals from 20 locations in varied parts of Sweden were analysed. The genetic distances of crucian carp populations indicated that the populations in the southernmost province of Sweden, Scania, shared a common history. A pond population in the province Småland also showed a common inheritance with this group. In the province Uppland, further north in Sweden, the population genetic distances suggested a much more complex history of crucian carp distributions in the ponds. The data showed that there are some ponds with potentially old populations without admixture, but also that several ponds might have been stocked with fish from many sources.
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| 8. |
- Lindsay, Willow, 1980, et al.
(författare)
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Endless forms of sexual selection
- 2019
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Ingår i: PeerJ. - : PeerJ. - 2167-8359. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- In recent years, the field of sexual selection has exploded, with advances in theoretical and empirical research complementing each other in exciting ways. This perspective piece is the product of a "stock-taking'' workshop on sexual selection and sexual conflict. Our aim is to identify and deliberate on outstanding questions and to stimulate discussion rather than provide a comprehensive overview of the entire field. These questions are organized into four thematic sections we deem essential to the field. First we focus on the evolution of mate choice and mating systems. Variation in mate quality can generate both competition and choice in the opposite sex, with implications for the evolution of mating systems. Limitations on mate choice may dictate the importance of direct vs. indirect benefits in mating decisions and consequently, mating systems, especially with regard to polyandry. Second, we focus on how sender and receiver mechanisms shape signal design. Mediation of honest signal content likely depends on integration of temporally variable social and physiological costs that are challenging to measure. We view the neuroethology of sensory and cognitive receiver biases as the main key to signal form and the 'aesthetic sense' proposed by Darwin. Since a receiver bias is sufficient to both initiate and drive ornament or armament exaggeration, without a genetically correlated or even coevolving receiver, this may be the appropriate 'null model' of sexual selection. Thirdly, we focus on the genetic architecture of sexually selected traits. Despite advances in modern molecular techniques, the number and identity of genes underlying performance, display and secondary sexual traits remains largely unknown. In-depth investigations into the genetic basis of sexual dimorphism in the context of long-term field studies will reveal constraints and trajectories of sexually selected trait evolution. Finally, we focus on sexual selection and conflict as drivers of speciation. Population divergence and speciation are often influenced by an interplay between sexual and natural selection. The extent to which sexual selection promotes or counteracts population divergence may vary depending on the genetic architecture of traits as well as the covariance between mating competition and local adaptation. Additionally, post-copulatory processes, such as selection against heterospecific sperm, may influence the importance of sexual selection in speciation. We propose that efforts to resolve these four themes can catalyze conceptual progress in the field of sexual selection, and we offer potential avenues of research to advance this progress.
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| 9. |
- Hallgren, Stefan, 1978-, et al.
(författare)
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Effects on Guppy brain aromatase activity following short-term steroid and 4-Nonyl phenol exposures
- 2010
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Ingår i: Environmental Toxicology. - : Wiley. - 1520-4081 .- 1522-7278. ; 25:3, s. 261-271
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Tidskriftsartikel (refereegranskat)abstract
- Brain oestrogen production, performed by the enzyme aromatase, can be disrupted/affected in teleost fish exposed to endocrine disruptors found in polluted aquatic environments. The guppy (Poecilia reticulata) was previously studied and confirmed to suffer negative effects on reproductive behaviours following inhibition of the brain aromatase reaction. Here Adult guppies (Poecilia reticulata) of both genders were subjected to known endocrine disruptors: the androgen androstenedione (A), the synthetic oestrogen 17α-ethynylestradiol (EE2) and the oestrogenic surfactant 4-nonylphenol (NP), at high (50 μg/L) and at environmentally relevant concentrations (10 ng/L EE2, 5 μg/L NP and 0.7 μg/L A) for two weeks followed by measurements of brain aromatase activity (bAA). In the adult males, bAA was stimulated by A and EE2 at 50 μg/L. Female activity was also stimulated by the higher oestrogenic treatment. At environmentally relevant concentrations only the EE2 treatment affected bAA, and only in males. The alkylphenolic substance NP produced no effect in either of the experiments, not on males nor females. The results indicate that short-term steroid treatments have stimulatory effects on guppy brain aromatase even at concentrations that can be found in the environment. We thus suggest bAA of adult guppies to be a suitable bioindicator of endocrine disruptors.
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| 10. |
- Lind, Emma E., 1974-, et al.
(författare)
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Directional genetic selection by pulp mill effluent on multiple populations of three-spined stickleback (Gasterosteus aculeatus)
- 2011
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Ingår i: Ecotoxicology. - : Springer Science and Business Media LLC. - 0963-9292 .- 1573-3017. ; 20:3, s. 503-512
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Tidskriftsartikel (refereegranskat)abstract
- Contamination can cause a rapid environmental change which may require populations to respond with evolutionary changes. To evaluate the effects of pulp mill effluents on population genetics, we sampled three-spined sticklebacks (Gasterosteus aculeatus) near four pulp mills and four adjacent reference sites and analyzed Amplified Fragment Length Polymorphism (AFLP) to compare genetic variability. A fine scale genetic structure was detected and samples from polluted sites separated from reference sites in multidimensional scaling plots (P < 0.005, 1000 permutations) and locus-by-locus Analysis of Molecular Variance (AMOVA) further confirmed that habitats are significantly separated (F-ST = 0.021, P < 0.01, 1023 permutations). The amount of genetic variation between populations did not differ between habitats, and populations from both habitats had similar levels of heterozygosity (polluted sites Nei's Hs = 0.11, reference sites Nei's Hs = 0.11). Still, pairwise F-ST: s between three, out of four, pairs of polluted-reference sites were significant. A F-ST-outlier analysis showed that 21 (8.4%) loci were statistically different from a neutral distribution at the P < 0.05 level and therefore indicated to be under divergent selection. When removing 13 F-ST-outlier loci, significant at the P < 0.01 level, differentiation between habitats disappeared in a multidimensional scaling plot. In conclusion, pulp mill effluence has acted as a selective agent on natural populations of G. aculeatus, causing a convergence in genotype composition change at multiple sites in an open environment.
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