In Evolution, Change Is the Only (Epigenetic) Constant

February 1, 2010 Most of us are thrown for a loop when conditions suddenly change, but some are better able to cope than others (we still haven’t gotten used to the new Facebook format). A recent PNAS paper by Johns Hopkins’ epi-gurus Andrew Feinberg and Rafael Irizarry makes the case that some of this adaptability stems from stochastic epigenetic variations. What’s more, the ability to vary epigenetic states with changing conditions can be passed on to descendants through a genetic mechanism.

According to their theory, individuals who can change the epigenetic states of certain gene promoters-for example, by dialing DNA methylation up or down-are better able to cope when environmental conditions take a turn for the worse. Underlying this epigenetic flexibility is a heritable genetic mechanism: SNPs in promoter regions add a C here or a G there, resulting in new opportunities for epigenetic control. Although the overall phenotype of the organism isn’t much different from others of its species, the enhanced flexibility to respond epigenetically to environmental challenges provides a survival advantage that can be passed on to offspring through natural selection.

The authors back up their theory with some interesting data and computer simulations that you can check out for yourself at PNAS, January 2010.