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Parallel evolution of site-specific changes in divergent caribou lineages
Rebekah L Horn1, Adam J D Marques2, Micheline Manseau3,4
1Trent University Peterborough ON Canada.
Ecology and Evolution
|July 11, 2018
Summary
Parallel evolution in North American caribou (Rangifer tarandus) reveals independent genetic changes in the cytochrome-b gene. This suggests different selective pressures drove similar trait evolution across distinct ancestral lineages.
Area of Science:
- Evolutionary biology
- Genomics
- Mammalian genetics
Background:
- Parallel evolution offers insights into evolutionary mechanisms and trait development.
- North American caribou (Rangifer tarandus) evolved from three distinct lineages post-Last Glacial Maximum.
- Introgression between North American and Beringian-Eurasian lineages is documented.
Purpose of the Study:
- To investigate the genetic basis of parallel evolution in caribou.
- To characterize functional differentiation within the cytochrome-b (cytB) gene.
- To assess site-specific parallel changes across caribou lineages.
Main Methods:
- Analysis of nonsynonymous changes in the cytochrome-b (cytB) gene.
- Comparative assessment of cytB gene sequences across caribou lineages (BEL, NAL, HAL).
- Identification of parallel amino acid substitutions.
Main Results:
- The North American lineage (NAL) exhibited greater functional diversity in cytB compared to the Beringian-Eurasian lineage (BEL).
- The BEL lineage showed higher neutral diversity.
- Observed patterns of amino acid substitutions supported parallel evolution of cytB, indicating lineage-specific selective pressures.
Conclusions:
- This study demonstrates the independent evolution of identical amino acid substitutions in caribou.
- Ecological niches likely drive parallel evolution in this wide-ranging mammal species.
- Findings highlight convergent genotypic evolution from divergent ancestral haplogroups.
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