Frugal fat or munificent muscle: genomic imprinting and metabolism

Variation in body composition is a popular obsession. The culturally ‘ideal’ body type is light on fat and heavy on muscle but the human population is collectively laying on fat. A new study finds antagonistic effects of two imprinted genes, Grb10 and Dlk1, on body composition in mice. These findings pose the question whether there is an evolutionary conflict between genes of maternal and paternal origin over the optimal proportions of body fat and lean muscle mass. See research article: http://www.biomedcentral.com/1741-7007/12/99