A research team led by Washington State University scientists analyzed the epigenetics—molecular factors and processes that determine whether genes are turned on or off—of a group of Poecilia mexicana fish, or Atlantic molly, that live in springs naturally high in hydrogen sulfide, which is normally toxic to most organisms.
“After two generations in laboratory conditions, the fish generally retained their same epigenetic marks, which was really unexpected,” said Joanna Kelley, WSU associate professor of evolutionary genomics and a corresponding author on the study published in Proceedings of the National Academy of Sciences. “In an evolutionary context, the study shows that these epigenetic marks are fairly stable.”
For this study, Kelley collaborated with WSU environmental epigenetics and reproductive biologist Michael Skinner, to do the epigenetic analysis. The researchers raised a sample of sulfidic and non-sulfidic fish in freshwater environments. When the fish produced two generations of offspring, they measured their epigenetic similarities, specifically regions of DNA methylation, a type of chemical modification that can regulate gene expression, turning a gene on or off, without changing the DNA sequence string itself.