What's Normal Again?

Carl Zimmer's scientific blog, The Loom, is always an excellent source for up-to-date biology news and theories. After a recent break, he is back with an intriguing piece on the state of current genetic studies on human DNA, specifically the search for the "original" Adam and Eve from whom we derive our stuff.

I was aware of the African Eve hypothesis that indicated all of our mitochondrial-DNA derives from a single female who lived in Africa about 200,000 years. But I was not aware of a similar search for the history of the male Y-chromosome. Research in that field suggests that the "Adam" of the Y all men currently carry lived about 60,000 years ago. Of course the story is a little more complicated than that, and Zimmer does a wonderful job of making clear the current work.

One intriguing aspect of this research is that monogamy seems an unlikely possibility for "normal" humans throughout most of our history. Polygyny, in which two or more women have children with a single man, seems more likely.

"Scientists have proposed that humans have a history of polygyny before (our sperm, for example, looks like the sperm of polygynous apes and monkeys, for example). But with these new DNA results, the Arizona researchers have made a powerful case that polygyny has been common for tens of thousands of years across the Old World. It's possible that polygyny was an open institution for much of that time, or that secret trysts made it a reality that few would acknowledge. What's much less possible is that monogamy has been the status quo for 50,000 years." [emphasis added]

Add this to the fact that there is now a mass of research on homosexuality in non-human animals, and one can easily understand why many of us treat Bush and Ashcroft's assertions that only monogamous relationships between one man and one woman are "normal" with the contempt that all bigoted remarks deserve.