| 471. |
- Hornfeldt, B, et al.
(författare)
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Sex ratio and fledging success of supplementary-fed Tengmalm's owl broods
- 2000
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Ingår i: MOLECULAR ECOLOGY. - : BLACKWELL SCIENCE LTD. - 0962-1083. ; 9:2, s. 187-192
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Tidskriftsartikel (refereegranskat)abstract
- A nest box population of Tengmalm's owls (Aegolius funereus) in northern Sweden was studied to investigate the effects of extra food on the sex ratio between hatching and fledging in this sexually size-dimorphic species. The brood size and brood sex ratio
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| 472. |
- Huang, Xi, et al.
(författare)
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Generalist haemosporidian parasites are better adapted to a subset of host species in a multiple host community
- 2018
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Ingår i: Molecular Ecology. - : Wiley. - 0962-1083. ; 27:21, s. 4336-4346
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Parasites that can infect multiple host species are considered to be host generalists with low host specificity. However, whether generalist parasites are better adapted to a subset of their host species remains unknown. To elucidate this possibility, we compared the variation in prevalence and infection intensity among host species of three generalist parasite lineages belonging to the morphological species Haemoproteus majoris, in a natural bird community in southern Sweden. Prevalence in each host species was confirmed by nested PCR and DNA sequencing and infection intensities were quantified using lineage-specific real-time qPCR. For two of the three lineages, we detected positive correlations between prevalence and infection intensity, indicating that these generalist parasites are better adapted to a subset of host species, which may have been more frequently encountered during the evolution of the parasite; we refer to these as main host species. For both lineages, the main host species were more phylogenetically related than expected by chance as revealed by strong phylogenetic signal in prevalence among hosts. By comparing our results with previous records of these parasites, we found that the host range of a generalist parasite can vary among different communities and may partly be shaped by the presence of other parasites. Our study reveals that generalist parasites may be specialized on a subset of their host species and it highlights the importance of considering infection intensity and host phylogeny when determining the host specificity of a parasite. This article is protected by copyright. All rights reserved.
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| 473. |
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| 474. |
- JAAROLA, M, et al.
(författare)
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COLONIZATION HISTORY OF NORTH EUROPEAN FIELD VOLES (MICROTUS-AGRESTIS) REVEALED BY MITOCHONDRIAL-DNA
- 1995
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Ingår i: MOLECULAR ECOLOGY. - : BLACKWELL SCIENCE LTD. - 0962-1083. ; 4:3, s. 299-310
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The genetic structure of field vole (Microtus agrestis) populations from northern Europe was examined by restriction fragment length polymorphisms of mitochondrial DNA (mtDNA) in 150 individuals from 67 localities. A total of 83 haplotypes was observed, m
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| 475. |
- Jaarola, Maarit, et al.
(författare)
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Phylogeography of field voles (Microtus agrestis) in Eurasia inferred from mitochondrial DNA sequences
- 2002
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Ingår i: Molecular Ecology. - 0962-1083. ; 11:12, s. 2613-2621
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Tidskriftsartikel (refereegranskat)abstract
- In a distribution-wide phylogeographic survey of the field vole (Microtus agrestis), 75 specimens from 56 localities across Eurasia were examined for DNA sequence variation along the whole 1140 base pair (bp) mitochondrial (mt) cytochrome b gene. The species is subdivided into three main mtDNA phylogeographic groups - western, eastern and southern - with largely allopatric distributions. The western phylogeographical group is found in west and central Europe and spread most probably from a glacial refugium in the Carpathians. The eastern group covers a large range from Lithuania to central Asia, and probably originated from a southeast European source (e.g. the southern Urals or the Caucasus). The southern group occupies an area from Portugal to Hungary, with division into two distinct mtDNA sublineages that presumably derive from separate glacial refugia in the Iberian Peninsula. Molecular clock estimates suggest that the western and eastern field vole populations separated during the last glaciation, whereas the southern population dates back 0.5-0.9 Myr. High levels of mtDNA variation indicate relatively large population sizes and subdivisions within phylogeographic groups during the last glaciation. We report a possible new suture zone in east Europe.
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| 476. |
- Johannesson, Kerstin, 1955, et al.
(författare)
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Life on the margin: genetic isolation and diversity loss in a peripheral marine ecosystem, the Baltic Sea.
- 2006
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Ingår i: Molecular ecology. - 0962-1083. ; 15:8, s. 2013-29
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Tidskriftsartikel (refereegranskat)abstract
- Marginal populations are often isolated and under extreme selection pressures resulting in anomalous genetics. Consequently, ecosystems that are geographically and ecologically marginal might have a large share of genetically atypical populations, in need of particular concern in management of these ecosystems. To test this prediction, we analysed genetic data from 29 species inhabiting the low saline Baltic Sea, a geographically and ecologically marginal ecosystem. On average Baltic populations had lost genetic diversity compared to Atlantic populations: a pattern unrelated to dispersal capacity, generation time of species and taxonomic group of organism, but strongly related to type of genetic marker (mitochondrial DNA loci had lost c. 50% diversity, and nuclear loci 10%). Analyses of genetic isolation by geographic distance revealed clinal patterns of differentiation between Baltic and Atlantic regions. For a majority of species, clines were sigmoid with a sharp slope around the Baltic Sea entrance, indicating impeded gene flows between Baltic and Atlantic populations. Some species showed signs of allele frequencies being perturbed at the edge of their distribution inside the Baltic Sea. Despite the short geological history of the Baltic Sea (8000 years), populations inhabiting the Baltic have evolved substantially different from Atlantic populations, probably as a consequence of isolation and bottlenecks, as well as selection on adaptive traits. In addition, the Baltic Sea also acts a refuge for unique evolutionary lineages. This marginal ecosystem is thus vulnerable but also exceedingly valuable, housing unique genes, genotypes and populations that constitute an important genetic resource for management and conservation.
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| 477. |
- Johnsen, A., et al.
(författare)
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Molecular and phenotypic divergence in the bluethroat (Luscinia svecica) subspecies complex
- 2006
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Ingår i: Molecular Ecology. - 0962-1083. ; 15:13, s. 4033-4047
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Tidskriftsartikel (refereegranskat)abstract
- Subspecies complexes may provide valuable insights into the early stages of the speciation process. The bluethroat (Luscinia svecica) consists of many morphologically distinct subspecies that differ most strikingly in the ornamental colour pattern of the male throat. We investigated the genetic and phenotypic differentiation in this subspecies complex, using (i) microsatellite genotyping (11 loci) of a sample of 364 individuals from bluethroat populations in Europe and Asia, and (ii) spectrometric and morphological measurements of a sample of 131 museum skin specimens. Population genetic analyses, based on microsatellite allele frequency variation, revealed a slight but significant overall population differentiation (F-ST = 0.042). There was a well-differentiated southern group of subspecies with white or no throat spots and a less-differentiated northern group of chestnut-spotted populations. Phylogenetic analyses indicated that the southern all-blue and white-spotted forms are ancestral to the chestnut-spotted subspecies. In addition to the qualitative variation in throat plumage pattern already described in the literature, we found significant quantitative variation among subspecies in hue, chroma and brightness of the ultraviolet (UV)/blue throat coloration, and this variation seemed to be unrelated to the phylogenetic distance between subspecies.
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| 478. |
- Jorde, P. E., et al.
(författare)
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Genetically distinct populations of northern shrimp, Pandalus borealis, in the North Atlantic: adaptation to different temperatures as an isolation factor
- 2015
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Ingår i: Molecular Ecology. - : Wiley. - 0962-1083. ; 24:8, s. 1742-1757
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Tidskriftsartikel (refereegranskat)abstract
- The large-scale population genetic structure of northern shrimp, Pandalus borealis, was investigated over the species' range in the North Atlantic, identifying multiple genetically distinct groups. Genetic divergence among sample localities varied among 10 microsatellite loci (range: F-ST=-0.0002 to 0.0475) with a highly significant average (F-ST=0.0149; P<0.0001). In contrast, little or no genetic differences were observed among temporal replicates from the same localities (F-ST=0.0004; P=0.33). Spatial genetic patterns were compared to geographic distances, patterns of larval drift obtained through oceanographic modelling, and temperature differences, within a multiple linear regression framework. The best-fit model included all three factors and explained approximately 29% of all spatial genetic divergence. However, geographic distance and larval drift alone had only minor effects (2.5-4.7%) on large-scale genetic differentiation patterns, whereas bottom temperature differences explained most (26%). Larval drift was found to promote genetic homogeneity in parts of the study area with strong currents, but appeared ineffective across large temperature gradients. These findings highlight the breakdown of gene flow in a species with a long pelagic larval phase (up to 3months) and indicate a role for local adaptation to temperature conditions in promoting evolutionary diversification and speciation in the marine environment.
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| 479. |
- Jouventin, P A, et al.
(författare)
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Genetic isolation and divergence in sexual traits: evidence for the northern rockhopper penguin Eudyptes moseleyi being a sibling species
- 2006
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Ingår i: Molecular Ecology. - 0962-1083. ; 15:11, s. 3413-3423
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Tidskriftsartikel (refereegranskat)abstract
- The taxonomic status of populations of rockhopper penguins (Eudyptes chrysocome) is still enigmatic. Northern populations differ from southern ones in breeding phenology, song characteristics and head ornaments used as mating signals. We conducted a molecular analysis using mitochondrial DNA sequencing to test if there is a gene flow barrier between northern (subtropical) populations and southern (subantarctic) populations in relation to the Subtropical Convergence, a major ecological boundary for marine organisms. Sequences of the control region and the ND2 gene were analysed in rockhopper penguins and in the macaroni penguin (Eudyptes chrysolophus), a closely related species. Genetic distances and phylogenetic analyses showed a clear split into three clades, two rockhopper clades and the macaroni penguin. Moreover, Theta(ST) and gene flow estimates also suggested genetic structuring within the northern rockhoppers. Our results add further support to the notion that the two rockhopper penguin taxa, often considered as two subspecies, can be recognized as two species E. chrysocome and E. moseleyi. The divergence in mating signals found between these two taxa seems to have occurred recently and relatively rapidly. Thus, the behavioural changes may have been enough to isolate these taxa without the need for morphological differentiation. The findings have important conservational implications, since E. moseleyi is far less abundant than E. chrysocome, but more populations may warrant an uplisting to endangered status if full species status should be recognized for more subpopulations.
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| 480. |
- Jørgensen, Tine, et al.
(författare)
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A comparative study of ancient sedimentary DNA, pollen and macrofossils from permafrost sediments of Northern Siberia reveals long-term vegetational stability
- 2012
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Ingår i: Molecular Ecology. - 0962-1083. ; 21:8, s. 1989-2003
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Tidskriftsartikel (refereegranskat)abstract
- Abstract in Undetermined Although ancient DNA from sediments (sedaDNA) has been used to investigate past ecosystems, the approach has never been directly compared with the traditional methods of pollen and macrofossil analysis. We conducted a comparative survey of 18 ancient permafrost samples spanning the Late Pleistocene (4612.5 thousand years ago), from the Taymyr Peninsula in northern Siberia. The results show that pollen, macrofossils and sedaDNA are complementary rather than overlapping and, in combination, reveal more detailed information on plant palaeocommunities than can be achieved by each individual approach. SedaDNA and macrofossils share greater overlap in plant identifications than with pollen, suggesting that sedaDNA is local in origin. These two proxies also permit identification to lower taxonomic levels than pollen, enabling investigation into temporal changes in species composition and the determination of indicator species to describe environmental changes. Combining data from all three proxies reveals an area continually dominated by a mosaic vegetation of tundra-steppe, pioneer and wet-indicator plants. Such vegetational stability is unexpected, given the severe climate changes taking place in the Northern Hemisphere during this time, with changes in average annual temperatures of >22 degrees C. This may explain the abundance of ice-age mammals such as horse and bison in Taymyr Peninsula during the Pleistocene and why it acted as a refugium for the last mainland woolly mammoth. Our finding reveals the benefits of combining sedaDNA, pollen and macrofossil for palaeovegetational reconstruction and adds to the increasing evidence suggesting large areas of the Northern Hemisphere remained ecologically stable during the Late Pleistocene.
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