Epigenetics drives weight differences between identical twins

http://www.eurekalert.org/pub_releases/2016-01/cp-edw012016.php

Public Release: 28-Jan-2016
Epigenetics drives weight differences between identical twins
Cell Press

Having overweight parents significantly increases your risk of obesity, but the inheritance of specific mutations can't always explain why this is the case. In a study published January 28 in Cell, researchers show that differences in gene expression and not the DNA sequence play a key role in determining one's predisposition to obesity. In genetically identical mice and human twin pairs, epigenetic marks altered the activity of weight-control genes to produce distinct subpopulations of lean and obese individuals. The findings reveal a key role for an epigenetic switch in explaining individual differences in obesity.

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Although the evolutionary implications are not entirely clear, it is likely that such epigenetic changes, which can be inherited or modified by environmental factors, could allow a species to adapt to or survive extreme conditions. For example, starvation may produce epigenetic changes that trigger the emergence of a distinct subpopulation of individuals that develop substantial fat stores. "A switch-like mechanism to produce individuals with different traits without changing DNA provides a selective advantage at the population level," Pospisilik says. "Polyphenism allows an emergency or plan B version that gets the species through transient selective pressures."

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