220W Poster - Population Genetics
Wednesday June 08, 8:30 PM - 9:15 PM

Authors:
Mark Bitter ¹; Sharon Greenblum ^1,2; Seth Rudman ^3,4; Subhash Rajpurohit ^{3, 5}; Nicolas Betancourt ^3,6; Mary Catherine Berner ³; Skyler Berardi ³; Dmitri Petrov ¹; Paul Schmidt ³

Affiliations:
1) Department of Biology, Stanford University, Stanford, CA; 2) DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Walnut Creek, CA; 3) Department of Biology, University of Pennsylvania, Philadelphia, PA; 4) School of Biological Sciences, Washington State University, Vancouver, WA ; 5) Division of Biological and Life Sciences, School of Arts and Sciences, Ahmedabad University, Navrangpura, Ahmedabad; 6) School of Medicine, Stanford University, Stanford, CA

Keywords:
Natural selection

Determining the tempo and repeatability of adaptation in natural populations is of central interest in evolutionary biology. Seasonal environments, which fluctuate cyclically and on a timescale that lends to repeated empirical observation, provide an excellent system within which to approach this venture. For example, Rudman et al. (2021) recently leveraged a single spring to fall transition, and a highly replicated, semi-natural mesocosm system, to demonstrate dynamic patterns of phenotypic and genomic evolution in Drosophila melanogaster. Notably, the study identified concurrent phenotypic evolution and large allele frequency shifts at numerous independent loci, with changes in the direction of selection throughout the sampling period. Still, inferring the generality of the observed dynamics hinges upon repeated quantification across independent years of sampling. Accordingly, using the same experimental system, I will present results of three additional years of genomics data to show that adaptive tracking of seasonal fluctuations in the environment is indeed a repeatable phenomenon in D. melanoagster. I will further discuss the extent to which the genetic basis of seasonal adaptation exhibits parallelism across multiple years of sampling. Finally, I will describe ongoing work aimed at drawing direct links between observed patterns of genetic and phenotypic variation within this system. Specifically, I will present results exploring discrepancies between the large-efect size loci underlying variation in a seasonally evolving trait, pigmentation, and those loci driving the evolution of the trait between the spring and fall.
References: Rudman S.M., et al. (2021) bioRxiv doi: 10.1101/2021.04.27.441526.