| Topic: |
Religions > Atheism |
| User: |
"johac" |
| Date: |
24 Apr 2007 06:46:05 PM |
| Object: |
'Junk' DNA now looks like powerful regulator |
Maybe not so much a junk pile as an attic.
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Stanford University Medical Center
'Junk' DNA now looks like powerful regulator, Stanford researcher finds
STANFORD, Calif. -- Large swaths of garbled human DNA once dismissed as
junk appear to contain some valuable sections, according to a new study
by researchers at the Stanford University School of Medicine and the
University of California-Santa Cruz. The scientists propose that this
redeemed DNA plays a role in controlling when genes turn on and off.
Gill Bejerano, PhD, assistant professor of developmental biology and of
computer science at Stanford, found more than 10,000 nearly identical
genetic snippets dotting the human chromosomes. Many of those snippets
were located in gene-free chromosomal expanses once described by
geneticists as "gene deserts." These sections are, in fact, so clogged
with useful DNA bits - including the ones Bejerano and his colleagues
describe - that they've been renamed "regulatory jungles."
"It's funny how quickly the field is now evolving," Bejerano said. His
work picking out these snippets and describing why they might exist will
be published in the April 23 advance online issue of the Proceedings of
the National Academy of Sciences.
It turns out that most of the segments described in the research paper
cluster near genes that play a carefully orchestrated role during an
animal's first few weeks after conception. Bejerano and his colleagues
think that these sequences help in the intricate choreography of when
and where those genes flip on as the animal lays out its body plan. In
particular, the group found the sequences to be especially abundant near
genes that help cells stick together. These genes play a crucial role
early in an animal's life, helping cells migrate to the correct location
or form into organs and tissues of the correct shape.
The 10,402 sequences studied by Bejerano, along with David Haussler,
PhD, professor of biomolecular engineering at UC-Santa Cruz, are
remnants of unusual DNA pieces called transposons that duplicate
themselves and hop around the genome. "We used to think they were mostly
messing things up. Here is a case where they are actually useful,"
Bejerano said.
He suspects that when a transposon is plopped down in a region where it
wasn't needed, it slowly accumulated mutations until it no longer
resembled its original sequence. The genome is littered with these
decaying transposons. When a transposon dropped into a location where it
was useful, however, it held on to much of the original sequence, making
it possible for Bejerano to pick out.
In past work, Bejerano and his co-workers had identified a handful of
transposons that seemed to regulate nearby genes. However, it wasn't
clear how common the phenomenon might be. "Now we've shown that
transposons may be a major vehicle for evolutionary novelty," he said.
The paper's first author, Craig Lowe, a graduate student in Haussler's
lab at UC-Santa Cruz, said finding the transposons was just the first
step. "Now we are trying to nail down exactly what the elements are
doing," he said.
Bejerano's work wouldn't have been possible without two things that
became available over the past few years: the complete gene sequence of
many vertebrate species, and fast computers running sophisticated new
genetic analysis software. "Right now it's like being a kid in a candy
warehouse," Bejerano said. Computer-savvy biologists have the tools to
ask questions about how genes and chromosomes evolve and change,
questions that just a few years ago were unanswerable.
Bejerano and his colleagues aren't the first to suggest that transposons
play a role in regulating nearby genes. In fact, Nobel laureate Barbara
McClintock, PhD, who first discovered transposons, proposed in 1956 that
they could help determine the timing for when nearby genes turn on and
off.
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http://www.eurekalert.org/pub_releases/2007-04/sumc-dn041907.php
--
John #1782
"We should always be disposed to believe that which appears to us to be
white is really black, if the hierarchy of the church so decides."
- Saint Ignatius Loyola (1491-1556) Founder of the Jesuit Order.
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| User: "GODEATER" |
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| Title: Re: 'Junk' DNA now looks like powerful regulator |
25 Apr 2007 11:52:08 AM |
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"johac" <jhachmann@remove.sbcglobal.net> wrote in message
news:jhachmann-3D35C8.16460524042007@news.giganews.com...
Maybe not so much a junk pile as an attic.
---
Stanford University Medical Center
'Junk' DNA now looks like powerful regulator, Stanford researcher finds
i allways suspected that.i mean,why would our DNA have "junk" in it?
we would all run like windows and crash alot-uhh-wait a minute!eureka moment
here!the likes of puke and chunks prove that they have true junk for
DNA-they constantly crash!
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| User: "johac" |
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| Title: Re: 'Junk' DNA now looks like powerful regulator |
25 Apr 2007 05:58:17 PM |
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In article <bfKdnbs0teaUGrLbnZ2dnUVZ_rylnZ2d@giganews.com>,
"GODEATER" <GODEATER@GODKILLER.ORG> wrote:
"johac" <jhachmann@remove.sbcglobal.net> wrote in message
news:jhachmann-3D35C8.16460524042007@news.giganews.com...
Maybe not so much a junk pile as an attic.
---
Stanford University Medical Center
'Junk' DNA now looks like powerful regulator, Stanford researcher finds
i allways suspected that.i mean,why would our DNA have "junk" in it?
we would all run like windows and crash alot-uhh-wait a minute!eureka moment
here!the likes of puke and chunks prove that they have true junk for
DNA-they constantly crash!
That's not really how it works. It was found that only certain regions
(sequences) of the genome get expressed, the exons. It was thought that
the 'junk' was left overs from evolution, with no function. Now we're
finding that it does have its uses, at least a portion of it.
--
John #1782
"We should always be disposed to believe that which appears to us to be
white is really black, if the hierarchy of the church so decides."
- Saint Ignatius Loyola (1491-1556) Founder of the Jesuit Order.
.
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