Project description:Although hydrogen sulfide is toxic to most organisms, a fish, Poecilia mexicana, has adapted to survive in environments with high levels of hydrogen sulfide. The epigenetic changes in response to this environmental stress were examined by assessing DNA methylation alterations in the nucleated red blood cells (RBC) in the fish. In addition to collecting wild males and females from sulfidic and non-sulfidic environments, wild males and females in these environments were collected and moved to a non-sulfidic environment in the laboratory and propagated for two generations in a non-sulfidic environment. We compared epimutations between sexes and field and laboratory populations. The F0 generation sulfidic wild fish were compared to the non-sulfidic wild fish and found to have significant differential DNA methylation regions (DMRs) in the RBC DNA. The F2 generation laboratory fish were also compared between the sulfidic and non-sulfidic populations, and a significant number of DMRs were also identified. The DMRs have stable generational inheritance in the absence of the sulfidic environment. The DMRs in the F0 generation wild fish had an over 80% overlap with the F2 generation laboratory non-sulfidic environment propagated fish. This is one of the first examples of epigenetic generational stability after the removal of an environmental stressor. The DMR associated genes were found to be relevant to sulfur toxicity and metabolism processes.
