Epigenetics in development.

It has become increasingly evident in recent years that development is under epigenetic control. Epigenetics is the study of heritable changes in gene function that occur independently of alterations to primary DNA sequence. The best-studied epigenetic modifications are DNA methylation, and changes in chromatin structure by histone modifications, and histone exchange. An exciting, new chapter in the field is the finding that long-distance chromosomal interactions also modify gene expression. Epigenetic modifications are key regulators of important developmental events, including X-inactivation, genomic imprinting, patterning by Hox genes and neuronal development. This primer covers these aspects of epigenetics in brief, and features an interview with two epigenetic scientists.