From darkness to discovery: evolutionary, adaptive, and translational genetic insights from cavefish.

How genotype determines phenotype is a well-explored question, but genotype-environment interactions and their heritable impact on phenotype over the course of evolution are not as thoroughly investigated. The fish Astyanax mexicanus, comprising surface and cave ecotypes, is an ideal emerging model to study the genetic basis of adaptation to new environments. This model has permitted quantitative trait locus (QTL) mapping and whole-genome comparisons to identify the genetic bases of traits such as albinism and insulin resistance and has helped in the better understanding of fundamental evolutionary mechanisms. In this review, we summarize recent advances in A. mexicanus genetics and discuss its broader impact on the fields of adaptation and evolutionary genetics.