Epigenetics of sex determination in mammals

AbstractEpigenetics 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 types of cells. Since all of them are derived from a single fertilized egg, their genotypes are identical. However, the gene expression patterns are different between the cell types, indicating that each cell type has unique own “epigenotype”. Epigenetic gene regulation mechanisms essentially contribute to various processes of mammalian development. The essence of epigenetic regulation is the structural change of chromatin to modulate gene activity in a spatiotemporal manner. DNA methylation and histone modifications ar e the major epigenetic mechanisms. Sex determination is the process for gender establishment. There are two types of sex-determining mechanisms in animals, environmental sex determination (ESD) and genotypic sex determination (GSD). Recent studies have provided some evidence that epigenetic mechanis ms play indispensable roles in ESD and GSD. Some fishes undergo ESD, in which DNA methylation is essentially involved. GSD is employed in therian mammals, whereSry (sex-determining region on the Y chromosome) triggers testis differentiation from undifferentiated gonads.Sry expression is tightly regulated in a spatiotemporal manner. A recent study demonstrated that histone modification is involved inSry regulation. In this review, we discuss the role of epigenetic mechanisms for sex determination in mam...
Source: Reproductive Medicine and Biology - Category: OBGYN Source Type: research