Epigenetics

When one considers inheritance, typically it is at the level of the DNA, gene, or chromosome: typical Mendelian genetics. However, not all hereditary [Page 336]information is passed on in our genes. The field that studies these heritable differences in gene expression that do not involve a change in the DNA sequence is called epigenetics. This field can include studies of how gene expression is modified as cells divide and differentiate into specific types; how environmental factors (such as chemicals or radiation) change the way genes are expressed; and how patterns of gene expression are passed on from parent to daughter cells.

All multicellular organisms start off from a single cell, which contains all the genetic information present in an organism. However, from this single cell, vastly ...