Quantitative trait loci (QTL) clustering in the Mexican cavefish genome
A major goal of modern evolutionary biology is connecting phenotypic evolution with its underlying genetic basis. The Mexican cavefish (Astyanax mexicanus), a characin fish species comprised of an ancestral surface ecotype and a derived cave-adapted ecotype, is well suited to study the genetic mechanisms underlying rapid adaptation to extreme environments. In this study, I mapped 206 previously published quantitative trait loci (QTL) for “troglomorphic” (cave-associated) traits to the newest version of the Astyanax genome assembly. I found that QTL for seemingly distinct troglomorphic traits cluster together in the genome more than expected by chance, suggesting that pleiotropic loci affecting multiple traits may play a key role in the Mexican cavefish’s rapid adaptation to the cave environment. Additionally, I generated robust lists of candidate genes that can serve as a starting point for future empirical research seeking to understand the genetic basis of troglomorphic traits in Astyanax mexicanus.