Musings on Epigenetics

The traditional evolutionary view of aging is that evolution cares to keep animals healthy through breeding and then through early offspring-raising age, but after that does not care as much about health.  Since lifespans and healthspans have increased by some 30 years over two centuries in the West,  people now live to more than double child-rearing age, that view is no longer tenable. For one thing, our genes have remained fairly stable and the explanation is not in
genetics. It is now known to be in epigenetics, modifications to DNA and RNA that profoundly effect gene expression.  These modifications can be acquired as a result of lifestyle and diet, are to some extent inheritable, and – this is important – are reversible.  

Epigenetics is the new idiom for explaining what is going on in our cells and bodies and is the subject of hundreds of new research publications appearing monthly.  To get technical, main mechanisms for changing the epigenome are DNA and RNA Methylation, Histone acetylation and micro-RNA expression.  Evolution has indeed been going on in humans, at a rapid rate.  But this evolution has been mainly in our epigenomes, not in our genes.