NYT: Still Evolving, Human Genes Tell New Story

[BlueEyedSon]

Wonder what the Creationist/ID folks will make of this...?

March 7, 2006
Still Evolving, Human Genes Tell New Story
By NICHOLAS WADE

Providing the strongest evidence yet that humans are still evolving, researchers have detected some 700 regions of the human genome where genes appear to have been reshaped by natural selection, a principal force of evolution, within the last 5,000 to 15,000 years.

The genes that show this evolutionary change include some responsible for the senses of taste and smell, digestion, bone structure, skin color and brain function.

Many of these instances of selection may reflect the pressures that came to bear as people abandoned their hunting and gathering way of life for settlement and agriculture, a transition well under way in Europe and East Asia some 5,000 years ago.

Under natural selection, beneficial genes become more common in a population as their owners have more progeny.

More: http://www.nytimes.com/2006/03/07/science/07evolve.html?_r=1&oref=slogin

[Viva_La_Revolution]

1. finally that silly idea that we stopped evolving might be put to rest.

I've never understood why it seemed to be the prevailing attitude, even among scientists.

"The finding adds substantially to the evidence that human evolution did not grind to a halt in the distant past, as is tacitly assumed by many social scientists. Even evolutionary psychologists, who interpret human behavior in terms of what the brain evolved to do, hold that the work of natural selection in shaping the human mind was completed in the pre-agricultural past, more than 10,000 years ago."

[phantom power]

3. There were some reasons.

One was that older evolution theories were gradualist, and evolution was assumed to occur very slowly. So, it wasn't so much that it had "stopped," but that the last 10K years weren't enough time for anything significant to have happened. We now know that evolution can happen more quickly than we used to assume.

Another is that agriculture and technology were assumed to have removed selection pressures from us. Of course, it merely replaced old selection pressures with new ones. But until you understand something, you don't :-)

[mzmolly]

7. The human brain is being challenged in new ways. 100 years

ago many people were farmers. They lived in calm rural areas and did a lot of physical work. Think about how drastically lives have changed in just the past century. Think about how differently we use our brains.

[BlueEyedSon]

4. Prior to this "discovery" I was inclined to think that the time scale of

evolution would be too long to be detectable. This is very good news.

[mzmolly]

5. Agreed. I am glad that the evolving brain is being discussed.

I think that as humans we are in varied states of evolutionary progress depending upon our ancestry.

Glad to see the scientific trend going in this direction.

[manic expression]

12. Well, there is little selective pressure

at least in developed countries. That is pretty much what drives a lot of the evolutionary process. So, I don't find that idea to be silly.

[Viva_La_Revolution]

17. so evolution has slowed to a crawl.

Still, I always thought it was a very short-sighted theory, and very pompous of us to think we were the only animals on the planet to have finished evolving.

[manic expression]

19. True

Sickle-cell and other developments would prove that very theory wrong. There isn't that much separating us from other species.

On a tangent, I think natural selection is likely not the only form of evolution, as epigenetics is gaining a lot of support now (neo-Lamarckism, you could call it).

[Viva_La_Revolution]

21. Hey! I just learned about Lamarckism! see #20

lol

:)

[lakercub]

26. Anybody who understands evolution

never said we were finished evolving. Every species is transitional...including ours.

[spunky]

27. Don't you wonder at all if modern medicine is impeding/preventing it?

I mean, in order for natural selection to occur, there has to be differential reproductive success. There is very little left that prevents you from surviving and reproducing. Childhood disease is about it. If you can make it to adulthood, and aren't sterile, you can reproduce. This has to have some sort of impact on evolution.

EDIT: Well, that and personal choice not to reproduce, but if anything this will have a negative effect on evolution, since it seems to be healthy, educated people who are choosing not to reproduce.

[phantom power]

2. I wonder what brain adaptations make it easier to live in cities?

Cities arose along with agriculture. Living with thousands, or millions of people is different than living in a smaller hunter/gatherer tribe. I can imagine both flattering and not-so-flattering adaptations.

[AlienGirl]

29. Probably neophilia

In mice, at least, neophilia is highly heritable. Among humans, I've seen that the ones who are highly neophobic prefer the relatively unchanging life that small towns and rural places offer, while the most neophilic like city living. If neophilia/neophobia is an inborn trait, it could explain why cities, as self-selected neophilic populations, tend to be more socially liberal while self-selected neophobic communities in rural areas tend toward conservatism.

I'm a neophilic sport of a neophobic family...

Tucker

[mtnester]

6. Nah, that is just God screwing with us

if he wanted us to know about evolution and dinsoaurs, he would tell us directly..it has nothing to do with us

(from the mouth of a fundie I heard this a long time ago)

[hobbit709]

8. That's because God

didn't want fundies and republicans to evolve any further than they already had. They're obviously an evolutionary dead-end.

[Bigmack]

9. Bullshit...

If humans are still evolving.....how do you explain Republicans? Devolution?
Living Neanderthals!

[phantom power]

11. Evolution only favors quantity. Direction or quality is unimportant.

Are liberals or conservatives more likely to breed big families?

[BlueEyedSon]

13. YIKES! Guess we libruls should stop being pro-choice!

[megatherium]

15. Are We Not Men?

We are DEVO!

[Viva_La_Revolution]

20. Devolution means a delegation of powers

The term Devolution, which normally means a delegation of powers, is sometimes erroneously used to refer to the evolution of a species into more "primitive" forms. Many lay people see evolution as "progress", reflecting the ideas of Lamarckism. However, scientists recognise that evolution by natural selection is directionless, and so "devolution" is still actually evolution.

Evolution and devolution
One of the most common misunderstandings of evolution is that one species can be "more highly evolved" than another, that evolution is necessarily progressive, or that its converse is "devolution". Evolution provides no assurance that later generations are more intelligent, complex, or morally worthy than earlier generations. The claim that evolution results in moral progress is not part of modern evolutionary theory - that claim is associated with Social Darwinism which held the subjugation of the poor and minority groups was favored by evolution.

In many cases evolution does involve "progression" towards more complexity, since the earliest lifeforms were clearly much simpler than many of the species existing today. In that sense, there clearly has been a gradual movement over time from simple organisms to complex - and in some cases intelligent - lifeforms. However, there is no guarantee that any particular organism existing today will become more intelligent, more complex, bigger, or stronger in the future. In fact, natural selection will only favor this kind of "progression" if it increases chance of survival. The same mechanism can actually favor lower intelligence, lower complexity, and so on if those traits become a selective advantage in the organism's environment.
http://en.wikipedia.org/wiki/Evolution#Evolution_and_devolution


So, evolution does explain Republicans! :)

[PsychoDad]

28. Evolution adheres to the law of...

"If it ain't broke, don't fix it". :)

Often times the "simpler" form is perfectly suited to it's niche, and so remains unchanged for eons.

:)

Peace

[JudyM]

25. "survival of the fittest" also applies to societal evolution

Raking it in at the expense of others may not be the highest moral good, but it sets them up to live comfortably and procreate all they want, and gives their offspring survival advantages. Not that this is necessarily the core of it for them. Also, to the extent that we're talking about the religious zealots, we know they're procreating at higher rates (there was on thread on DU within the past couple days about that) and discouraged from using birth control, etc.

This article is one of the most fascinating I read during the '04 election - the brain psychophysiology behind Bush's popularity:

http://www.alternet.org/columnists/story/20168

[spunky]

10. I find that interesting, but I'd like to see the actual journal article

Diversity could be decreasing because breeding populations were more isolated. With the onset of agriculture, you become sedintary, and therefore aren't going to come in contact with as many groups as you did when you made a yearly round, so I don't see how that alone is evidence of continued evolution.

Also, they don't state how these genes and any changes they cause in physiology increase reproductive success. That's my issue with the question of continued evolution. Our modern life allows us to live long enough to reproduce with conditions that previously would have led to decreased reproductive success.

[BlueEyedSon]

14. If it's on the web you will find it quite easily with google.

[geomon666]

16. Genes were put there by Satan.

Genes hate America too and these researchers take their orders from Bin Laden.

[TechBear_Seattle]

18. Case in point: Lactose tolerance

Most mammals lose the ability to digest lactose (milk sugar) after about 1/20th of their average lifespan, at about the same time they are weaned. Humans are one of the very few able to digest lactose in to adulthood, and only 30% of adult humans can do even that. The genetic mutation that allows this seems to have developed about the same time that cattle were domesticated, about 5,000 to 6,000 years ago.

[Viva_La_Revolution]

22. Yep. People of European decent mostly

they relied heavily on milk as a staple, when most other societies didn't.

[phusion]

23. also many African nomadic herding tribes

that rely on milk from their cattle.

[TechBear_Seattle]

24. From what I've learned

There are three major variations in the gene that normally shuts off production of lactase, the enzyme that allows lactose to be digested. One variation is found in Europe, roughly from Scandanavia in to France and the Iberian peninsula, south to Italy and then around the north and east Mediterranean into areas that had been dominated by the Roman Empire (surprise, surprise.) A second, different variation can be found from Greece through Asia Minor, east to the Himalayas and from there south in to India, roughly the same areas dominated by the Aryan peoples. A third variation, presumably the most modern as it is the least widespread, is found among the Masai people of Africa and scattered among groups with close ties to the Masai.

Pretty much everyone else on the planet loses the ability to digest milk at between 2 and 3. It can be retained somewhat in these people, if they have a steady supply of lactose in their diet, but their ability to digest it will be greatly diminished and can be easily lost. Individuals who can consume high-lactose products through adulthood either have a... let's call it a "local" mutation, or they have inherited a mutation from an ancestor.

It is also possible for someone from a population with the mutation to lose the ability to digest lactose. Sadly, I'm one of them. I can still eat moderate amounts of hard cheese and yogurt with no problem, as these have little lactose. If I mess up and have sour cream or cottage cheese or ricotta or a glass of milk, however... :puke:

Could be worse, though. I had a friend in college who would get ill if he ate a few cookies made with butter. Most people aren't quite that bad, though.

There is a funny/sad story about some of the first famine relief efforts in Africa during the late 50s. These programs relied on milk as a cheap, available supply of protein, and it took white American do-gooders a long time to figure out why the milk was making people in Africa much sicker than they were before.