25 Oral - Platform Session #2 Genetics of Adaptation
Wednesday June 08, 5:00 PM - 5:15 PM
Evolutionary consequences of domestication on the selective effect of new mutations in canids
Authors: Carlos Eduardo Guerra Amorim 1; Clare Marsden 2; Jonathan Mah 2; Miguel Guardado 3; Bernard Kim 4; Jacqueline Robinson 3; Robert Wayne 2; Kirk Lohmueller 2
Affiliations: 1) California State University Northridge; 2) University of California Los Angeles; 3) University of California San Francisco; 4) Stanford University
Keywords: Natural selection
Domestication created radical phenotypic changes in many species and understanding the genetic basis of these changes is a major research objective. Recent studies suggest that the domestication of canids has increased the load of deleterious mutations, simplified the genetic architecture of complex traits, and increased runs of homozygosity in the dog genome. What remains unclear is whether domestication has also altered the distribution of fitness effects (DFE) of new mutations due to shifted selective pressures. Specifically, strongly deleterious mutations may have become less deleterious in domesticated populations living alongside humans, while neutral mutations underlying traits of interest may have been selected by breeders. We address this question by leveraging whole-genome sequence data from 23 grey wolves and 61 dogs. We observe nonsynonymous to synonymous ratios ranging from 0.61-0.71 across the different populations of wolves and dogs. After accounting for differences in demography and background selection, we find that the DFE is similar across canids, with ~36% of new amino acid-changing mutations being neutral (s<0.0001), and ~43% under strong purifying selection (s>0.01). We evaluate the robustness of our results to different model assumptions and conclude that the DFE is stable across short evolutionary timescales, despite putative drastic changes in the selective pressure caused by artificial selection during domestication and breed formation. On par with previous works describing DFE evolution across the tree of life, we hypothesize that the DFE depends more strongly on organismal characteristics and less so on shifting selective pressures.