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- Chen, J, et al.
(författare)
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New insights on the speciation history and nucleotide diversity of three boreal spruce species and a Tertiary relict
- 2010
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Ingår i: Heredity. - : Springer Science and Business Media LLC. - 0018-067X .- 1365-2540. ; 104:1, s. 3-14
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Tidskriftsartikel (refereegranskat)abstract
- In all, 10 nuclear loci were re-sequenced in four spruce species. Three of the species are boreal species with very large natural ranges: Picea mariana and P. glauca are North American, and P. abies, is Eurasian. The fourth species, P. breweriana, is a Tertiary relict from Northern California, with a very small natural range. Although the boreal species population sizes have fluctuated through the Ice Ages, P. breweriana is believed to have had a rather stable population size through the Quaternary. Indeed, the average Tajima’s D was close to zero in this species and negative in the three boreal ones. Reflecting differences in current population sizes, nucleotide diversity was an order of magnitude lower in P. breweriana than in the boreal species. This is in contrast to the similar and high levels of heterozygosity observed in previous studies at allozyme loci across species. As the species have very different histories and effective population sizes, selection at allozyme loci rather than demography appears to be a better explanation for this discrepancy. Parameters of Isolation-with-Migration (IM) models were also estimated for pairs of species. Shared polymorphisms were extensive and fixed polymorphisms few. Divergence times were much shorter than those previously reported. There was also evidence of historical gene flow between P. abies and P. glauca. The latter was more closely related to P. abies than to its sympatric relative P. mariana. This last result suggests that North American and Eurasian species might have been geographically much closer in the recent past than they are today.
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| 2. |
- Foster, KR, et al.
(författare)
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Colony kin structure and male production in Dolichovespula wasps
- 2001
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Ingår i: MOLECULAR ECOLOGY. - 0962-1083. ; 10:4, s. 1003-1010
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Tidskriftsartikel (refereegranskat)abstract
- In annual hymenopteran societies headed by a single outbred queen, paternity (determined by queen mating frequency and sperm use) is the sole variable affecting colony kin structure and is therefore a key predictor of colony reproductive characteristics.
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| 9. |
- Seppa, P., et al.
(författare)
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Mosaic structure of native ant supercolonies
- 2012
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Ingår i: Molecular Ecology. - : Wiley. - 0962-1083 .- 1365-294X. ; 21:23, s. 5880-5891
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Tidskriftsartikel (refereegranskat)abstract
- According to the inclusive fitness theory, some degree of positive relatedness is required for the evolution and maintenance of altruism. However, ant colonies are sometimes large interconnected networks of nests, which are genetically homogenous entities, causing a putative problem for the theory. We studied spatial structure and genetic relatedness in two supercolonies of the ant Formica exsecta, using nuclear and mitochondrial markers. We show that there may be multiple pathways to supercolonial social organization leading to different spatial genetic structures. One supercolony formed a genetically homogenous population dominated by a single mtDNA haplotype, as expected if founded by a small number of colonizers, followed by nest propagation by budding and domination of the habitat patch. The other supercolony had several haplotypes, and the spatial genetic structure was a mosaic of nuclear and mitochondrial clusters. Genetic diversity probably originated from long-range dispersal, and the mosaic population structure is likely a result of stochastic short-range dispersal of individuals. Such a mosaic spatial structure is apparently discordant with the current knowledge about the integrity of ant colonies. Relatedness was low in both populations when estimated among nestmates, but increased significantly when estimated among individuals sharing the same genetic cluster or haplogroup. The latter association indicates the important historical role of queen dispersal in the determination of the spatial genetic structure.
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