:^)
Posted on 12/11/2007 12:34:37 AM PST by anymouse
Human evolution has been moving at breakneck speed in the past several thousand years, far from plodding along as some scientists had thought, researchers said on Monday.
In fact, people today are genetically more different from people living 5,000 years ago than those humans were different from the Neanderthals who vanished 30,000 years ago, according to anthropologist John Hawks of the University of Wisconsin.
The genetic changes have related to numerous different human characteristics, the researchers said.
Many of the recent genetic changes reflect differences in the human diet brought on by agriculture, as well as resistance to epidemic diseases that became mass killers following the growth of human civilizations, the researchers said.
For example, Africans have new genes providing resistance to malaria. In Europeans, there is a gene that makes them better able to digest milk as adults. In Asians, there is a gene that makes ear wax more dry.
The changes have been driven by the colossal growth in the human population -- from a few million to 6.5 billion in the past 10,000 years -- with people moving into new environments to which they needed to adapt, added Henry Harpending, a University of Utah anthropologist.
"The central finding is that human evolution is happening very fast -- faster than any of us thought," Harpending said in a telephone interview.
"Most of the acceleration is in the last 10,000 years, basically corresponding to population growth after agriculture is invented," Hawks said in a telephone interview.
The research appears in the journal Proceedings of the National Academy of Sciences.
FAVORABLE GENE MUTATIONS
The researchers looked for the appearance of favorable gene mutations over the past 80,000 years of human history by analyzing voluminous DNA information on 270 people from different populations worldwide.
Data from this International HapMap Project, short for haplotype mapping, offered essentially a catalogue of genetic differences and similarities in people alive today.
Looking at such data, scientists can ascertain how recently a given genetic change appeared in the genome and then can plot the pace of such change into the distant past.
Beneficial genetic changes have appeared at a rate roughly 100 times higher in the past 5,000 years than at any previous period of human evolution, the researchers determined. They added that about 7 percent of human genes are undergoing rapid, relatively recent evolution.
Even with these changes, however, human DNA remains more than 99 percent identical, the researchers noted.
Harpending said the genetic evidence shows that people worldwide have been getting less similar rather than more similar due to the relatively recent genetic changes.
Genes have evolved relatively quickly in Africa, Asia and Europe but almost all of the changes have been unique to their corner of the world. This is the case, he said, because since humans dispersed from Africa to other parts of the world about 40,000 years ago, there has not been much flow of genes between the regions.
Brief applause and small flag waving for your correct use of “infer.” And at 3:00 a.m. (Eastern) too!
Have a nice day!
:^)
Selective pressure? One problem I see is that the most “successful” among us see little or no pressure to reproduce.
the less you understand the more of a higher creature is necessary for explanation.
Humans are evolving you say?? Into what? Got any evidence of humans with claws or wings or poison fangs or anything like that, i.e. any evidence of REAL/MACRO evolution in humans??
That’s funny, humans are getting dumber and dumber, look how many will vote for Hillary! LOL
As anyone who has sat through a ball game at Fenway Park can attest.........
You’re welcome.
So, the cause of the extinction of the Neanderthals may have been discovered. They couldn’t receive dental treatments because they couldn’t be anesthetized in the oral region, and they all died of complications of gingivitis.
The area of the human genome that is contained within genes is a fraction of the total DNA. Genes themselves are comprised of promoters, enhancers, upstream and downstream regulatory sequences, coding and non-coding sections of the message. The coding parts, that are the blueprint for the proteins or RNAs, are themselves small parts of the entire gene.
I'm not sure if the researchers here are using the word "gene" in the context of the entire gene with all the regulatory sequences included, or just the part of the gene that codes for a product (which is also a correct use of the word).
Either way, when the researchers state that 7 percent of the genes are undergoing rapid evolution, they are talking about a very small fraction of the entire human genome.
That apparent short circuiting also allows mutations to survive that may weaken the individual in some areas, yet strengthen them in others. IOW the gene pool is getting bigger.
There has always been a circularity about natural selection as an explanation of evolution., Anyway, given the obvious role that culture plays in the cnages that have been observed, determinism and chance both seems to have been overemphasized, and human intellligence and morality played down. In any case, the whole effort to connect us with chimps seems odd. The more they learn, the more they find out how relatively fixed human nature is. The course was set and what they call evolution is more like the development of an individual human. You are what you think and do:
That’s what evolution is.
Biologists talk about it as change in allele ratios over time. Alleles are the different forms a gene can take. Oversimplified example: green, blue, hazel and brown eyes could all be alleles of one gene. If that gene were to mutate you might get purple eyes. If blue eyes couldn’t see as well and the people with them couldn’t find food, over time there’d be fewer of them. That’s evolution.
Translated, that means adaptions that don’t hurt stay in the population. Adaptations that help, increase.
That’s selective pressure, but not with the result you’d like.
In evolutionary terms, reproducing trumps graduating.
You seem to be forgetting that even two hundred years ago, the human population was much smaller. Better nutrition explains the population explosion better than anything. Even a hundred years ago, many people in London were malnourished. Interesting to read Charlie Chapalin’s autobiography. He was small because he grew up without much food. The Japanese today are much larger than their great grandparents.
A lot of fuss could be avoided if evolutionists would use the term “adaptation rather than “evolution.” Human culture seems to control this process far more than anything that other animal species can do, because there number of choices is so much less. Let the biologists study bugs.
If the biologists only study bugs, who gets to study people?
So, how does evolution really work? Maybe there are other answers.
There are hundreds of genes involved in this.
Besides white folks having changed to be better able to eat dairy products as adults, the Chinese appear to have changed to accommodate a rice diet.
Eskimos, Sa'ami and other Polar People can eat more meat and fat than you can imagine and keep their cholesterol and triglycerides within reasonable bounds.
And so on.
Forsooth. In particular, Japanese girls are much, um, 'larger' than their grandmoms.
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