PROJECT SUMMARY
Understanding the genetic variation that underlies differences in survival and reproduction is
essential to the study of biology and human disease. While most studies of adaptation have
focused on traits driven by loci of large effect, the majority of variation in survival and
reproduction is due to variation at complex traits, which involve many loci throughout the
genome and are influenced by the environment. The majority of these human trait associations
are found in non-coding regions, suggesting that genetic variants that affect gene regulation
play an important role in trait variation and fitness. However, few studies have been able to
connect genetic variants affecting gene expression with complex traits in natural populations,
limiting our understanding of the genomics of adaptive evolution. The overarching goal of this
work is to identify specific loci involved in complex trait variation affecting fitness in natural
populations. Previous work has often fallen short of this goal due to (1) a lack of power for
detecting variants of small or modest effect involved in trait variation, or (2) the difficulty of
linking variants under selection to traits in natural populations. The proposed work will overcome
this limitation by integration studies of tissue-specific assays of gene regulation, surveys in
natural populations, and the use of new sequencing and computational approaches. First, we
will identify gene regulatory variation associated with ecologically and biomedically significant
traits (e.g., body mass and composition, blood chemistry measures, renal physiology, and
behavior/activity level) by combining tissue-specific measures of allele-specific expression and
chromatin accessibility with population genomic scans for selection. Then, we will use
ecologically relevant treatments to examine the effect of environmental variation on gene
expression levels and identify gene-by-environment interactions, as well as test the importance
of these interactions to adaptive evolution. Finally, we will use scRNA-seq data and gene
regulatory network reconstruction to examine how gene regulatory networks evolve in the
process of adaptation. Altogether, this work will directly address the challenge of connecting
genotype to phenotype for complex traits with implications for the genetics of human health and
disease.