I had planned to write a new post on the genetic origins of OCD today.
But whilst scanning new research, I learned that this effort will take a bit of time. The situation anno 2017 is markedly different from that in, say, 2007.
For instance, there’s the vast field of epigenetics, it has been expanding at a rapid pace. I quote this brief explanation from Wikipedia:
Epigenetics are stable heritable traits (or “phenotypes“) that cannot be explained by changes in DNA sequence. The Greek prefix epi- (Greek: επί– over, outside of, around) in epigenetics implies features that are “on top of” or “in addition to” the traditional genetic basis for inheritance. Epigenetics often refers to changes in a chromosome that affect gene activity and expression, but can also be used to describe any heritable phenotypic change that does not derive from a modification of the genome, such as prions. Such effects on cellular and physiological phenotypic traits may result from external or environmental factors, or be part of normal developmental program. The standard definition of epigenetics requires these alterations to be heritable, either in the progeny of cells or of organisms.
Epigenetics is the key link between our DNA proper and our environment. The old expression to describe the interaction between genes and surroundings is: G x E.
I am almost inclined to say: the mysterious x-factor in this small formula is epigenetics.