| Topic: |
Religions > Atheism |
| User: |
"johac" |
| Date: |
16 Nov 2005 07:57:06 AM |
| Object: |
'Perception' gene tracked humanity's evolution |
We are getting more and more clues as to how the human brain evolved and
what differentiates us from other primates.
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'Perception' gene tracked humanity's evolution, scientists say
A gene thought to influence perception and susceptibility to drug
dependence is expressed more readily in human beings than in other
primates, and this difference coincides with the evolution of our
species, say scientists at Indiana University Bloomington and three
other academic institutions. Their report appears in the December issue
of Public Library of Science Biology.
The gene encodes prodynorphin, an opium-like protein implicated in the
anticipation and experience of pain, social attachment and bonding, as
well as learning and memory.
"Humans have the ability to turn on this gene more easily and more
intensely than other primates," said IU Bloomington computational
biologist Matthew Hahn, who did the brunt of the population genetics
work for the paper. "Given its function, we believe regulation of this
gene was likely important in the evolution of modern humans' mental
capacity."
Prodynorphin is a precursor molecule of the neurotransmitters
alpha-endorphin, dynorphin A, and dynorphin B, collectively called
opioids because their action is similar to stimulatory effects caused by
the drug opium.
The notion that humans are more perceptive than other primates would
hardly be news. But the list of genes known to have tracked or guided
humanity's separation from the other apes is a short one. Genes
controlling the development of the brain almost always turn out to be
identical or nearly so in chimpanzees and human beings. And as it turns
out, the protein prodynorphin is identical in humans and chimps.
It's the prodynorphin gene's promoter sequence -- upstream DNA that
controls how much of the protein is expressed -- where the big
differences are. "Only about 1 to 1.5 percent of our DNA differs from
chimpanzees," Hahn said. "We found that in a stretch of DNA about 68
base pairs in length upstream of prodynorphin, 10 percent of the
sequence was different between us and chimps."
Hahn said this "evolutionary burst" is responsible for differences in
gene expression rates. When induced, the human prodynorphin gene was 20
percent more active than the chimpanzee prodynorphin gene. Past research
has also observed variation in expression levels within humans.
This report supports a growing consensus among evolutionary
anthropologists that hominid divergence from the other great apes was
fueled not by the origin of new genes, but by the quickening (or
slowing) of the expression of existing genes.
Hahn and his colleagues at Duke University, University College London
and Medical University of Vienna first became interested in primate
prodynorphin after noticing an unusual amount of variation in the human
version's promoter. The scientists decided to examine the prodynorphin
gene in human beings around the world and in non-human primates to see
whether such variation was commonplace and whether that variation
affected gene expression.
The group found a surprisingly large amount of genetic variation among
humans within the prodynorphin gene's promoter. They examined
prodynorphin genes from Chinese, Papua New Guineans, (Asian) Indians,
Ethiopians, Cameroonians, Austrians and Italians.
The group also sequenced and cloned prodynorphin genes from chimpanzees,
gorillas, orangutans, rhesus macaques, pigtail macaques and guinea
baboons. The researchers found that high genetic variation in the
prodynorphin promoter was unique to humans. Other primates' promoters
were far more homogeneous.
Exactly how prodynorphin influences human perception is unknown.
Evidence for its various effects comes entirely from clinical studies of
people who have mutations in the gene. Past clinical studies have also
indicated a positive correlation between lower prodynorphin levels in
the brain and susceptibility to cocaine dependence.
Matthew Rockman, David Goldstein and Gregory Wray (Duke University);
Nicole Soranzo (University College London); and Fritz Zimprich (Medical
University of Vienna) also contributed to the research. It was funded by
grants from the National Science Foundation, NASA, the Royal Society,
and the Leverhulme Trust (U.K.).
---
http://www.eurekalert.org/pub_releases/2005-11/iu-gt111405.php
--
John Hachmann aa #1782
"Those who can make you believe absurdities can make you commit atrocities"
-Voltaire
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| User: "Michael Gray" |
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| Title: Re: 'Perception' gene tracked humanity's evolution |
17 Nov 2005 11:15:46 AM |
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On Tue, 15 Nov 2005 23:57:06 -0800, johac <jhachm@ixpres.remove.com>
wrote:
We are getting more and more clues as to how the human brain evolved and
what differentiates us from other primates.
---
'Perception' gene tracked humanity's evolution, scientists say
A gene thought to influence perception and susceptibility to drug
dependence is expressed more readily in human beings than in other
primates, and this difference coincides with the evolution of our
species, say scientists at Indiana University Bloomington and three
other academic institutions. Their report appears in the December issue
of Public Library of Science Biology.
:
Pastor Dave seems to have skipped this gene.
Devolution at work.
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