Parallel evolution despite low genetic diversity in three-spined sticklebacks
When populations repeatedly adapt to similar environments they can evolve similar phenotypes based on shared genetic mechanisms (parallel evolution). The likelihood of parallel evolution is affected by demographic history, as it depends on the standing genetic variation of the source population. The...
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Published in | Proceedings of the Royal Society. B, Biological sciences Vol. 291; no. 2020; p. 20232617 |
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Main Authors | , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
England
The Royal Society
10.04.2024
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Subjects | |
Online Access | Get full text |
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Summary: | When populations repeatedly adapt to similar environments they can evolve similar phenotypes based on shared genetic mechanisms (parallel evolution). The likelihood of parallel evolution is affected by demographic history, as it depends on the standing genetic variation of the source population. The three-spined stickleback (
) repeatedly colonized and adapted to brackish and freshwater. Most parallel evolution studies in
were conducted at high latitudes, where freshwater populations maintain connectivity to the source marine populations. Here, we analysed southern and northern European marine and freshwater populations to test two hypotheses. First, that southern European freshwater populations (which currently lack connection to marine populations) lost genetic diversity due to bottlenecks and inbreeding compared to their northern counterparts. Second, that the degree of genetic parallelism is higher among northern than southern European freshwater populations, as the latter have been subjected to strong drift due to isolation. The results show that southern populations exhibit lower genetic diversity but a higher degree of genetic parallelism than northern populations. Hence, they confirm the hypothesis that southern populations have lost genetic diversity, but this loss probably happened after they had already adapted to freshwater conditions, explaining the high degree of genetic parallelism in the south. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 Electronic supplementary material is available online at https://doi.org/10.6084/m9.figshare.c.7132044. |
ISSN: | 0962-8452 1471-2954 |
DOI: | 10.1098/rspb.2023.2617 |