Humans Evolving Faster Than Ever

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."

Comments

This this not evolution

[Ubi_NL]

Acquisition of mutations is not evolution. Evolution is the combination of variations AND selection of those traits that increase fitness. The fact that we only acquire more genetic mutations means that selectionhas gone down and evolution with it. The simple explanation is that healt care enabled us to cheat on selection.

Re:This this not evolution

[Fallingcow]

What does "help" mean, in an evolutionary context?

Seems to me that culture is just another factor to which an organism may, over generations, adapt.

Re:This this not evolution

[Arancaytar]

Wrong.

Humans are still reproducing, surviving and dying. Traits are still selected. They're just different traits than the ones that would have been selected if humanity were still living in caves. The fitness function has been loosened, and the net is cast wider now - instead of mutations having to benefit (or not adversely affect) the immediate survival of the individual, there is more room for variety.

A species with a secured infrastructure can afford to gamble on outliers, who would not have survived prior to modern technology. Those gambles can pay off big-time. The absence of an outdated pre-civilization fitness function killing everyone with motor paralysis is what allows our species to benefit from a genius with motor paralysis.

Re:This this not evolution

[Hognoxious]

Evolution can occur on things that aren't coded in DNA. Software, for example.

Dawkins, memes. Does that ring a bell?

Re:This this not evolution

[Qbertino]

What health care was there 200 generations ago?

Pretty good healthcare in some parts of the world. Arabia and parts of the Byzantine Era, for instance, were a high culture more than a thousand years ago with complete health care coverage and other public services. Including stuff you'd have considered high-tech right up to magical in other parts of the world. Water clocks, aquaeducts, mechanical devices, sophisticated smithery and metal working, a school system, superiour math, accounting and efficiency measurement techniques, etc. As for the public healthcare, there are written acounts of people being thrown out of hospitals because they were still enjoying the pampering even though they were well again.

Which, on a sidenote, goes to show how things go down the drain once religious fanatics take over.

Re:This this not evolution

[tmosley]

That was ten generations ago, not 200. Westerners tend to have a very narrow view of history that assumes that the way things were in the dark ages is the way they were in all of pre-history. Couldn't be further from the truth. The truth is that the ancients had many techniques that have only been recently rediscovered, and we didn't actually surpass them until the late 1800's or early 1900's. I would rather be treated by a doctor from ancient Egypt than one from America circa 1820.

Re:This this not evolution

[RabidReindeer]

I should add that selection based on culture (love, pre-arranged weddings etc) rather than fitness also does not help evolution.

Your definition of "fitness" is not the Darwinian definition. It sounds, in fact, more like the pseudo-Darwinian conceit that "fitness" means the ability to kill or resist being killed. When Darwin said "survival", he didn't mean "last person on the island", he meant that the species in question had found a niche where its population would be stable.

Survivability comes in many forms. Some, like tigers are primarily solitary. Some, like herd animals, depend on the group. We have ample evidence these days that in many cases, survivability (in the Darwinian sense), can come even from relatives who never directly contribute DNA to the continuation of the species.

Love as a primarily positive evolutionary trait can be debated, although certainly being unlovable isn't going to afford many non-violent ways to swim in the gene pool. Pre-arranged weddings, on the other hand, can make the difference between a tribe being exterminated or being able to ally itself with other tribes. Systems of laws and mores can ensure that the unlovable whose sole means of propagation is rape will be taken out of circulation relatively quickly.

Social structures as evolutionary forces are not unique to the human race. But they are a powerful contributor. If we went strictly on kill or be killed based on physical fitness, we probably wouldn't have produced a Stephen Hawking.

Re:It's "Survival of the Fit-enough"...

[wvmarle]

All those babies surviving is something of the last five, maybe ten generations at most. And that's in the Western world. TFA is talking about 200 generations.

Times of plenty

[chrisjbuck]

I think population dynamics show that in times of plenty (little natural selection, abundant food) populations explode, what the human population has been doing the last 100+ years. It's the spring that doesn't come or massive outbreak of disease or new dominant predator that culls the population, when that selection occurs the random genetic variations may give rise to competitive advantages. It is only after the population goes through the selection event that any mutations that proved advantageous will spread right through the population, then the population has evolved. Before the selection event the population is just randomly diverging.

True!

[rew]

Absolutely true!

Evolution works that way: In good times, a big population is generated that has great genetic variety. When bad times come along, the bad genetic variations will be removed from the population.

Suppose for instance that suddenly tomorrow all oaktrees had pollen that is deadly to most humans. The genetic variations builtup over the last 200 years might have provided a (possibly small) percentage of the population that is resistant to the deadly pollen. The result would be that a small group survives and starts working on a new gene-pool.

Yes, genetically we have been living in "good times" the last generations. More and more "slight defects" in the genetic pool are able to survive into mature ages.

A friend is totally colorblind. A genetic disadvantage, you'd say? Nope, his "grayvision" is a LOT better than that of most of us. Apparently he can spot camouflaged army-material from way further away than us normal people. When suddenly THAT becomes a winning trait (i.e. those that don't have it die), his descendants will form a larger part of the population.

This expansion of the gene pool also allows for combinations. Suppose the guy with the super-vision marries the gal with the super hearing?

Re:Summary shows poor understanding of evolution

[EmagGeek]

I think what the submitter was getting as was that we are carrying a higher load of negative traits because natural selection is failing to eliminate them.

For example, one reason cancer is becoming more and more prevalent is because people who would normally die from it before they can reproduce, are instead being kept alive through technology to reproduce and transmit their higher susceptibility to cancer to the next generation.

(please not that I said "one reason," not "the only reason," because I know some environmental hot head is going to flame me for saying this)

Re:first

[MrKaos]

trolololol

Millions of years of genetic variation has produced....this