Skip to comments.Human Evolution: The More the Merrier
Posted on 09/03/2006 12:47:12 AM PDT by neverdem
Researchers peering into the DNA toolbox have found yet another instrument of evolution. Simply replicating a piece of a particular gene--from one copy in mice to more than 200 in humans--may have prompted some of the changes in the brain that define us as human, according to a new study.
Evolution occurs when genes mutate, or when they alter where, when, and how strongly they are active. In addition, hiccups in DNA replication can foster change by causing some parts of genes to be repeated as they are copied. Twin genes or duplicated regulatory regions result, and although one in the pair usually has to keep doing its original job, the other is free to mutate and take on new roles that can enhance an organism's survival.
In earlier work, James Sikela, a genome researcher at the University of Colorado, Denver, and Jonathan Pollack from Stanford University and colleagues found 134 genes that had been duplicated primarily after human ancestors split off from other primates. In the new study, Sikela, Gerald Wyckoff from the University of Missouri, Kansas City, and their colleagues compared the sequences of these genes in primates, as well from mice and rats, to reconstruct the history of each duplicated gene.
They found 44 genes with more than five copies each in the human genome. One in particular, called MGC8902, caught their eye. Humans have 49 copies of this gene, while chimps have 10 and macaques have four, the team reports tomorrow in Science. With so many copies, "MGC8902 stands out as a very good candidate to be important to a human specific trait," says Sikela. A closer look revealed that the heavily-duplicated gene contained its own duplications: six copies of a domain called DUF1220.
The domains exist in other primates, but are most common in humans, says Sikela. The researchers discovered that the genes with the DUF1220 domains are expressed in the heart, spleen, skeletal muscle, and small intestine, and are particularly active in the brain's neocortex. Thus, they may play a role in higher cognition.
"The exciting thing here is the expansion of a gene family associated with expression in specific neurons," says Evan Eichler, a geneticist at the University of Washington, Seattle. But, he adds, "I would be cautious about overextrapolating these observations to brain enlargement."
Interesting that the latest significant evolutionary advancement of mankind is the development of a belief in God.
No other animal has it, it is very recent, and it is almost singularly responsible for the creation and advance of civilization.
The most Enlightened and advanced humans believe in God. (Atheists are retro and share the property with the animal kingdom, who are also atheist._
I guess you missed the latest poll, majority of Americans now believe in evolution. Apparently we are now on that path to 'survival', that is if the funding doesn't dry up.
Duplication is a particularly powerful mutation.
Oh? And how do you know that animals are atheists?
I would love to know what methodology you used to divine the religious beliefs of, say, dogs.
FReepmail me if you want on or off my health and science ping list.
Interesting that you interpret it thus. The principal brain function that separates humans from other animals is abstract thinking -- something beyond stimulus and response that leads us not just to observe that things as they are, but to wonder how and why they are as they are.
That level of abstraction leads both to religion and to science. Different people find different answers. The evolutionary advance is the one that raised the questions.
It is possible, though I personally doubt it, that other animal species have the capacity to contemplate abstract questions and form philosophical abstracts to answer them, but we don't know it because we haven't yet managed to decipher their language.
Humans are almost certainly the only species that has managed to record its knowledge in a persistent form, so that each generation can began where the last left off rather than starting over.
You misspelled, "supported by a vast amount of evidence and research".
What's mere speculation is your opinion on this topic.
Being that every human is contained within the 'animal kingdom' that's not surprising.
Since all animals are atheist, therefore all H. sapien (it means 'human' for those of you in Pensacola) are also atheist?
Then again, maybe not. Ponder this classic observation:
"Primates often have trouble imagining a universe not run by an angry alpha male" -- AnonThat alone could be the source of the instinct to seek someone to obey/follow/submit to, and that would not be limited to humans. It certainly fits in a great number of ways.
It also explains why my dog worships me, and my cat doesn't. Creatures which have evolved a social structure revolving around an alpha-male (like dogs, as well as humans and other primates) will be "hardwired", instinctually, to expect and want a "ruler" to whom they give their allegiance and turn to for protection and permission.
Similarly, Arthur C. Clarke has suggested that man looks for a god because of the instincts which help us survive as a species having a long childhood. To keep kids from wandering off on their own too soon and getting eaten by the tigers beyond the safety of the tribe (and so on), humans, primates, and other animals with a long nurturing time have instincts which instill in the young feelings involving turning to your parents for protection and sustenance, looking up to them for guidance on how to live, fear of straying too far from them and being alone, respect for their position of power over you, etc. etc. etc. After growing up and/or leaving home, however, these instincts leave a yearning to continue to look up to some more powerful, protective nurturer/rule-giver. And a belief in a watching-over-me deity would fulfill this need for some people. Is it mere coincidence that so many gods are described in terms which are variations of "heavenly father", "our father who art in heaven", "god the father", etc.?
and it is almost singularly responsible for the creation and advance of civilization.
You're kidding, right? There are many things that are responsible for the "creation and advance of civilization", but a belief in one or more deities is *way* down on the list. Nothing beats a good education, but for a layman's intro you could do worse than reading the book "Guns, Germs, and Steel: The Fates of Human Societies" by Jared Diamond.
The most Enlightened and advanced humans believe in God. (Atheists are retro and share the property with the animal kingdom, who are also atheist.
Oh, excuse me, I mistook you for someone who wanted to have an actual discussion of the article, instead of someone who just wanted to make himself feel good by patting himself on the back as one of the "most Enlightened and advanced" while insulting millions of other people as being little better than animals. I won't make that mistake again.
Since animals are incapable of higher cognition, the worst they can be accused of is agnosticism.
No other animal has it....
Please ping me if proof of this is ever offered, I expect to live maybe twenty to thirty more years.
"Atheists are retro and share the property with the animal kingdom, who are also atheist._
You know, saving your insults for another venue might well be a good idea. Since human beings are also animals, your point is poorly constructed. It's also unseemly.
Told you that did they?
I think it would be more proper to say that they are probably agnostic. Atheists believe there is no God. Agnostics don't have an opinion either way.
Many of the early civilizations. Roman, Greek, Persian, various Chinese and Indian civilizations, believed in many Gods, or revere some (possibly mythical but still human) person.
What a dumb comment.
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