Subterranean Fishes of the World

3278

2017

AIM 2017

The two morphs of Astyanax mexicanus – the surface and the cave forms – have adapted to contrasting habitats during evolution. Cave environments offer limited or seasonally restricted food supply and consequently, the cave-dwelling populations had to drastically adjust their metabolism to withstand long starvation periods. To that end, they have adapted themselves to store large amounts of fat and tolerate diabetes-like symptoms albeit without any negative effects such as fatty liver and glucose intolerance. Much of these adaptive traits gained during evolution can be attributed to sequence-level changes in the genome. These changes can be the result of both coding and non-coding changes. While coding mutations can bring about changes directly to the structure and/or function of the protein, non-coding mutations can result in changes in expression level, spatial and/or temporal patterns of gene expression leading to varied phenotypes without pleiotropic effects. In this study, we focus to unravel the non-coding mutations that li ma y be helping cavefish survive adverse living conditions and remain healthy. We have performed ATAC-seq and ChIP-seq for histone modifications and p300 on livers of Surface, Pachón and Tinaja to narrow down to differential regulatory regions like enhancers and promoters. Studying these differentially active regulatory regions will help us understand how metabolic adaptation has evolved at the gene regulatory level in cavefish.

1