Humans Evolving Faster Than Ever 253
Kwyj1b0 writes "In a massive study on genetic variation among humans, researchers found that most changes have occurred in the last 200 generations, too fast for natural selection to catch up. Recent papers show that rare genetic variations have a more drastic effect than previously believed. Another result shows that 'we carry a much larger load of deleterious variants' (as well as positive variants) than our ancestors 200 generations ago."
Re:This this not evolution (Score:3, Interesting)
I should add that selection based on culture (love, pre-arranged weddings etc) rather than fitness also does not help evolution.
Re:It's "Survival of the Fit-enough"... (Score:5, Interesting)
The frightening aspect of this is that population may expand its genetic diversity to fill the 'fit enough" gene pool. Then it will overflow the "fit enough" gene pool by creating mutations that can't survive even with health care, bringing survival back down, albeit with increased genetic variety such that many can't survive without constant medical treatment.
That is to say, we will evolve to require medical treatment.
Re:This this not evolution (Score:2, Interesting)
So is fabrication of fire arms, but both are not evolution in theway we have defined the term evolution.
Re:It's "Survival of the Fit-enough"... (Score:5, Interesting)
Your natural body is just a device for building a brain and a pair of gonads, at that point, and selective pressures only work on it in this scenario are those that render cyborg-you sterile, destroy your brain before it can be transplanted into a cyberbody, or make you better able to talk a partner into raising a family with you.
Re:This this not evolution (Score:5, Interesting)
Idiocracy could happen, but not necessarily due to biology. It's always possible to have a moron revolution that sticks. We nearly had an asshole revolution in the 40s. The dark ages we're basically idiocracy.
Re:This this not evolution (Score:5, Interesting)
At least the peacock is natural. We're looking at selecting for things which are acquired through surgery and hair extensions, i.e. things bought with money. That's pretty much the same as selecting for shallow self-centeredness.
Re:This this not evolution (Score:5, Interesting)
So is fabrication of fire arms, but both are not evolution in theway we have defined the term evolution.
Well you're right in that if we saw people with machine guns slaughter guys with muskets, we wouldn't call that evolution. Neither is going from 6-7 children/woman to 2-3 children/woman as many countries have done in a generation or two. It's only evolution if there's a reasonably clear link between your genetic makeup and your ability/probability to reproduce. I don't see much chance that a random mutation would help me survive a bullet, though there's a good chance that personality traits that are genetic could help me avoid a situation (or worse, put me in a situation) where I get shot. That's real evolutionary pressure right there, though I think the number of people shot and killed is too small to have any real significance.
But in terms of culture then genetics is a huge part of attractiveness, including appearance, personality and intelligence. That can have both direct effects to hooking up and indirect effects like social circle, social status and economic status. And perhaps even far more so today, how many kids you want to have. Sure society is a huge influence here but ultimately it comes down to personal choice that may be a lot more built in than people realize. Changing culture also makes different genes important, in a society with pre-arranged marriages your courtship genes might not matter much but in a society of free selection they do. That is a new selection pressure right there.
Re:This this not evolution (Score:5, Interesting)
Two errors here. First, you mean fitness, not evolution. Second, only the charismatic megafauna of our genetic endowment has a "reasonably clear" one paragraph synopsis. Try to figure out whether a small affinity change of some obscure serotonin receptor involved in bone growth regulation is deleterious or not. I dare you.
The rest of your post seems to be spinning around the observation that the genetic fitness function is shaped by cultural memes, which are themselves co-evolving. It's almost as if natural selection has no master plan.
Let's do a thought experiment. Imagine you have a cluster of ten genes where having eight of the A alleles makes you a genius, nine make you more than a little batshit, and the full set of ten make you A Scanner Darkly on a bad trip. On the other side, having five or fewer amounts to destination short bus. Clearly the A alleles of these genes code for smartness, and we all want that.
But then, if two eights pair up and start a family, you end up with The Royal Tenenbaums.
What happens within the population to the proportion of A alleles of this gene cluster? For the vast majority of people, an extra dose of the A allele would boost their intellectual powers and presumably their reproductive fitness. There would broadly be an increase. But then you lose enough to Van Gogh attrition that it cancels out the bulk upward drift.
Likely outcome: a barber pole that spins, but goes nowhere. Yet everyone presumes there's some direction clearly labeled as "up" within the genetic pell mell.
I listened to a podcast recently where a professor said that his students are routinely shocked to discover that simple voting systems contain cycling majorities.
If Condorcet's paradox [wikipedia.org] disorients, what's really going on in evolution is Kowloon Walled City [wikipedia.org] (which had a population density of 1,255,000 inhabitants per square kilometer before it was torn down, roughly what you'd get if everyone in Texas moved to Manhattan, as they framed it at 99% Invisible [99percentinvisible.org]).
We really ought to step back most of the time and view evolution as a kind of ideal gas law, as something best understood at the sweep of statistical mechanics. Yes, every atom is doing something explicable if you prefer to drill down. So was every inhabitant of Kowloon Walled City, more or less.