Genetic Influences

Epigenetic Factors
Another area of genetic research, which may explain functional changes in human development that are not related to an identifiable genetic mutation, is the field of epigenetics. Epigenetic influences change gene expression over time without affecting the genes themselves. Currently, there are several areas of study in epigenetic research, such as DNA methylation, RNA-associated silencing and histone modification. These areas of genetic research focus on the causes of inappropriate gene expression, where genes are silenced or gene expression is increased, decreased or ill timed. Factors that change cell signaling during gestation can also be considered epigenetic influences if the program for later gene activation is affected by these factors. One example of this could be the effects of fetal beta2 adrenergic receptor over stimulation during pregnancy, which has been demonstrated in rat studies to cause enhanced or deficient production of the signaling molecule, cyclic AMP, over time in development, in different areas of the brain. This altered cyclic AMP production then increases or decreases activation of many genes during gestation and postnatal life.