Meeting Abstract
Both protein coding and regulatory variation may contribute to local adaptation to the abiotic environment. We tested for contributions of each of these to heat adaptation in the copepod Tigriopus californicus by hybridizing populations that were divergent for heat tolerance, and then selecting for increased heat tolerance in hybrids over ten generations. Heat-selected lines had greater heat tolerance, but also diminished plasticity of gene expression and greater baseline expression of transcripts involved in the plastic response to heat stress. Genotyping of heat-selected lines also revealed increased frequencies of southern alleles for several genes, most notably for heat shock protein 70. Our results are consistent with findings from an array of other taxonomic groups, suggesting that both coding sequence variation and changes in gene regulation typically contribute to intraspecific variation in environmental tolerance.
