Ancient polymorphisms contribute to genome-wide variation by long-term balancing selection and divergent sorting in Boechera stricta
Journal
Genome Biology
Journal Volume
20
Journal Issue
1
Date Issued
2019
Author(s)
Wang B.
Mojica J.P.
Perera N.
Lee C.-R.
Lovell J.T.
Sharma A.
Adam C.
Lipzen A.
Barry K.
Rokhsar D.S.
Schmutz J.
Mitchell-Olds T.
Abstract
BACKGROUND: Genomic variation is widespread, and both neutral and selective processes can generate similar patterns in the genome. These processes are not mutually exclusive, so it is difficult to infer the evolutionary mechanisms that govern population and species divergence. Boechera stricta is a perennial relative of Arabidopsis thaliana native to largely undisturbed habitats with two geographic and ecologically divergent subspecies. Here, we delineate the evolutionary processes driving the genetic diversity and population differentiation in this species. RESULTS: -islands with elevated divergence, which have experienced directional selection, are derived from divergent sorting of ancient polymorphisms. CONCLUSIONS: Our results suggest that long-term balancing selection on disease resistance genes may have maintained ancestral haplotypes across different geographical lineages, and unequal sorting of balanced polymorphisms may have generated genomic regions with elevated divergence. This study highlights the importance of ancestral balanced polymorphisms as crucial components of genome-wide variation.
Type
journal article