Epigenetic regulation of mammalian sex determination.

Epigenetics is the study of changes in gene function that cannot be explained by changes in DNA sequence. A mammalian body contains more than two-hundred different types of cells, all derived from a single fertilized egg. Epigenetic gene regulation mechanisms essentially contribute to various processes of mammalian development. The essence of epigenetic regulation is the modulation of gene activity through changes in chromatin structure. DNA methylation and histone modifications are the major epigenetic mechanisms. Sex determination is the process of establishing a gender. Sry, the sex-determining gene in therian mammals, initiates testis differentiation. Recent studies have provided evidence that epigenetic mechanisms contribute to Sry regulation.