DNA Methylation and X Inactivation

DNA methylation and X-chromosome inactivation help control which genes are turned on or off. These epigenetic changes alter the physical structure of DNA without changing the DNA sequence. They help each cell make only the proteins it needs. For example, bone growth proteins are not made in muscle cells.

Epigenetic changes are modifications in gene expression that can be inherited by daughter cells or passed down through generations without modifications to the genetic sequence.

These modifications can occur during embryo development as a regulatory process, or they can be caused by environmental factors, such as diet, exposure to toxic s...