Genomic diversity landscapes in outcrossing and selfing < i > Caenorhabditis < /i > nematodes

by Anastasia A. Teterina, John H. Willis, Matt Lukac, Richard Jovelin, Asher D. Cutter, Patrick C. PhillipsCaenorhabditis nematodes form an excellent model for studying how the mode of reproduction affects genetic diversity, as some species reproduce via outcrossing whereas others can self-fertilize. Currently, chromosome-level patterns of diversity and recombination are only available for self-reproducingCaenorhabditis, making the generality of genomic patterns across the genus unclear given the profound potential influence of reproductive mode. Here we present a whole-genome diversity landscape, coupled with a new genetic map, for the outcrossing nematodeC.remanei. We demonstrate that the genomic distribution of recombination inC.remanei, like the model nematodeC.elegans, shows high recombination rates on chromosome arms and low rates toward the central regions. Patterns of genetic variation across the genome are also similar between these species, but differ dramatically in scale, being tenfold greater forC.remanei. Historical reconstructions of variation in effective population size over the past million generations echo this difference in polymorphism. Evolutionary simulations demonstrate how selection, recombination, mutation, and selfing shape variation along the genome, and that multiple drivers can produce patterns similar to those observed in natural populations. The results illustrate how genome organization and selection play a crucial role in shaping the genomic ...
Source: PLoS Genetics - Category: Genetics & Stem Cells Authors: Source Type: research