Human-specific derived alleles of CD33 and other genes protect against postreproductive cognitive declineThere's something special about a granny. Granddads are special too of course, but not quite like a granny. Ask my grandchildren.
Grandparents are biologically, on the face of it, a little bit of a mystery especially in a social species and especially in one like humans where for most people for most of the time until the discovery of agriculture, life consisted mostly of hunting and gathering food. Anyone not capable of joining in would have been a drain on the resources of those who could so it seems logical to suppose that any process which removed surplus people from the group after their fertile and productive years were over would be advantageous to the group and so would be expected to evolve. In fact, when you look at our closest relatives, chimpanzees, you find that the females tend to die soon after their fertility ceases.















