Fish that live in springs containing toxic hydrogen sulfide have a pattern of DNA methylation that appears to be inherited even in the absence of the compound, researchers report. High concentrations of hydrogen sulfide are toxic to most organisms, but a species of fish native to southern Mexico lives in springs naturally rich in the compound. Joanna L. Kelley, Michael Skinner, and colleagues report that Poecilia mexicana collected from springs containing hydrogen sulfide have a particular pattern of DNA methylation and that this epigenetic signature appears to be inherited even in the absence of the compound. The authors compared the DNA methylation patterns of eight P. mexicana individuals collected in sulfidic springs with those of seven individuals isolated from nonsulfidic springs to determine whether these epigenetic alterations, which can influence gene expression, occur in response to adaptation to hydrogen sulfide. The methylated regions of the two groups overlapped by approximately 20%. The authors also compared the methylation patterns of a subsequent generation of each population reared in the laboratory in the absence of high hydrogen sulfide concentrations. The second generation, or grandoffspring, of the hydrogen sulfide-tolerant population maintained an 80% overlap in areas of DNA methylation, even in the absence of hydrogen sulfide. According to the authors, heritable epigenetic mutations maintained in the absence of toxic agents could aid adaptation.
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Article #20-14929: "Epigenetic inheritance of DNA methylation changes in fish living in hydrogen sulfide-rich springs," by Joanna L. Kelley et al.
MEDIA CONTACTS: Joanna L. Kelley, Washington State University, Pullman, WA; tel: 206-979-1080; email: < joanna.l.kelley@wsu.edu >; Michael Skinner, Washington State University, Pullman, WA; tel: 509-335-1524; email: < skinner@wsu.edu >
Proceedings of the National Academy of Sciences