Wednesday, March 09, 2005

Gene wading pool?

Why am I not surprised? It seems humans got shortchanged when it comes to genetic diversity:
Unlike our close genetic relatives - chimps - all humans have virtually identical DNA. In fact, one group of chimps can have more genetic diversity than all of the six billion humans alive today.

It is thought we split from a common ancestor with chimps 5-6 million years ago, more than enough time for substantial genetic differences to develop.

The absence of those differences suggests to some researchers that the human gene pool was reduced to a small size in the recent past, thereby wiping out genetic variation between current populations.
Now, of course, this explains the eerie zombie-bot communal groupthink and wifeswapping ways of flyover country, but where did the rest of us come from?
A new hypothesis about recent human evolution suggests that we came very close to extinction because of a "volcanic winter" that occurred 71,000 years ago.

Some scientists estimate that there may have been as few as 15,000 humans alive at one time.

The volcanic winter lasted about six years. It was followed by 1,000 years of the coldest Ice Age on record.

It brought widespread famine and death to human populations around the world. It also affected subsequent human evolution.

This was because of a so-called bottleneck effect. The rapid decrease, in our ancestors' populations, in turn, brought about the rapid differentiation - or genetic divergence - of the surviving populations.
Aha! of course the 'bottleneck effect'! Now I see.

It's just like when you keep your Beam in the freezer -- you know, for that great freezing-burning 'taste' -- so the bottleneck gets really really cold and it gets hard to pour it into the shot glass (well, especially after so many shots) so you get that spillover and you're cursing is all garbled and whiz-bang you're speaking in a different language! The reemergence of human diversity. And the spilt Beam that calls to you to suck it up in a straw or... but I digress! is like all of the outliers -- you know, all of us who don't wifeswap (despite the messages beamed to us by TV) plus the redheads, lefties, libertarians, actors and the folks with webbed toes -- who make life such a rich pageant.

Moral of the story: preserve your genetic diversity by just saying 'NO' to wifeswapping with corn-fed midwesterners and drink your Beam straight from the bottleneck.