RNA sequencing of fish from hydrogen-sulfide rich environments in Mexico, the Dominican Republic, and the United States

We sequenced mRNA from the gill tissue of 84 individual fishes across 9 poeciliid species found in both hydrogen sulfide-rich springs and non-sulfidic environments (7 non-sulfidic populations, 7 sulfidic populations, 6 individuals per population; 10 samples were sequenced twice to achieve similar depth of coverage across all samples). We used this RNAseq approach to identify differentially expressed genes between the sulfidic and non-sulfidic populations of each species, as well as to characterize patterns of molecular evolution to identify genes that have experienced positive selection in sulfidic lineages.