Can human longevity be explained by “grandmother selection”? i.e., is there a selectable benefit in staying alive long enough that one can act to increase the fitness of one’s grandchildren?

Maybe, but apparently there isn’t any “grandfather selection” — at least according to the paper analyzed today over at Gene Expression, in this article:

The relative lack of a strong effect suggests that the long lives of grandfathers are simply a byproduct of the long life of grandmothers (analogous to the breasts that males have), or, that in the relatively recent past males exhibited far higher reproductive skew (polygyny, etc.) which resulted in continuous reproduction through their lifetime.

So male longevity is one step below a spandrel; it’s like a spandrel’s nipple.

A bit of meta-blogging: This is the first of hopefully many examples of me doing a better job of reading other science blogs and linking to cool aging-related posts.

As a further teaser, I also have a whole folder of bookmarks on sex-related issues in the evolution of aging, which I started accumulating after a colleague emailed me a fascinating but incredibly dense review he’d written on the subject. At the time I was too intimidated to write a post about it at the time, but I’ve promised myself to address the subject at length before the end of the month. It’s fascinating. Girls and boys, see, is different. Watch this space for details.