| Topic: |
Religions > Atheism |
| User: |
"johac" |
| Date: |
17 Aug 2006 01:26:25 AM |
| Object: |
Possible key human evolution genes identified |
More evidence.
---
Possible key human evolution genes identified
By Jeremy LovellWed Aug 16, 1:05 PM ET
They could be the missing links of human genetic evolution -- areas of
human DNA that changed dramatically after the evolutionary division from
chimpanzees, though they had remained almost unchanged for millennia
before.
Scientists from the United States, Belgium and France identified 49
"human accelerated regions" (HARs) showing a lot of genetic activity.
In the most active, identified as HAR1, they found 18 out of the 118
nucleotides had changed since evolutionary separation from chimps some 6
million years ago, while only two had changed in the 310 million years
separating the evolutionary lines of chimps and chickens.
"Right now we have very suggestive evidence that it might be involved at
a critical step in brain development, but we still need to prove that it
really makes a difference," team leader David Haussler from the Howard
Hughes Medical Institute and the University of California, Santa Cruz
told Reuters.
Other members of the team came from the University of Brussels and
Universite Claude Bernard in France.
"It is very exciting to use evolution to look at regions of our genome
that haven't been explored yet," Haussler said.
"It is extremely unlikely that the evolution of just one region in the
genome made the difference between our brains and the brains of
non-human primates," he said.
"It is much more likely to be a series of many, many small changes, each
very important, but none doing the entire job by itself," he added.
HAR1 is part of a novel RNA gene HAR1F that is produced during the key
formative period for the human brain from seven to 19 weeks of gestation.
Not only that, but the RNA is produced by the Cajal-Retzius neuron that
plays a crucial role in the six layers of neurons in the human cortex.
"We still can't say much about the function. But it's a very exciting
finding because it is expressed in cells that have a fundamental role in
the design and development of the mammalian cortex," Haussler said,
noting the need to investigate the remaining 48 HARs.
The findings were published on Wednesday in the science journal Nature.
Chris Ponting of Oxford University wrote in the same issue hailing it as
a possible major step forward.
"Previously, the hunt for changes in DNA that are causally linked to
human-specific biology had concentrated on differences that would alter
the amino-acid make-up of the encoded protein," Ponting wrote.
"Now it would seem that searches within the functional non-coding 'dark
matter' might be more enlightening," he added.
---
http://news.yahoo.com/s/nm/20060816/ts_nm/science_evolution_dc
--
John Hachmann aa #1782
"Those who can make you believe absurdities can make you commit atrocities"
-Voltaire
Contact - Throw a .net over the .com
.
|
|
|
Related Articles |
|
|
