Personal genomes: The case of the missing heritability : Nature News

Personal genomes: The case of the missing heritability : Nature News: "Epigenetics, changes in gene expression that are inherited but not caused by changes in genetic sequence, confuses things further. Feeding a mouse a certain diet, for example, can alter the coat colour not only in its children, but also in its children's children11. Here, the expression of a coat-colour gene is controlled by a type of DNA modification called methylation, but it's not completely clear how that methylation pattern is 'remembered' by the next generation. The idea that grandma's environment could affect future generations is controversial — and such effects would have been included in the heritability normally attributed to genes."