Received: by alpheratz.cpm.aca.mmu.ac.uk id IAA13573 (8.6.9/5.3[ref pg@gmsl.co.uk] for cpm.aca.mmu.ac.uk from fmb-majordomo@mmu.ac.uk); Tue, 12 Feb 2002 08:41:21 GMT Date: Tue, 12 Feb 2002 00:35:40 -0800 Message-Id: <200202120835.g1C8ZeXr026828@mail25.bigmailbox.com> X-Authentication-Warning: mail25.bigmailbox.com: www set sender to joedees@addall.com using -f Content-Type: text/plain Content-Disposition: inline Content-Transfer-Encoding: binary X-Mailer: MIME-tools 4.104 (Entity 4.116) X-Originating-Ip: [65.80.162.88] From: "Joe Dees" <joedees@addall.com> To: memetics@mmu.ac.uk Subject: RE: [Fwd: That's about it for Creationism...er...I mean, Intelligent DesignHypothesis] Sender: fmb-majordomo@mmu.ac.uk Precedence: bulk Reply-To: memetics@mmu.ac.uk('binary' encoding is not supported, stored as-is)
>Date: Fri, 08 Feb 2002 16:06:03 -0800
> "Michael M. Butler" <butler@comp-lib.org> "extropians@extropy.org" <extropians@extropy.org>Reply-To: extropians@extropy.org
>
>http://ucsdnews.ucsd.edu/newsrel/science/mchox.htm has the nifty images.
>
>Graphic and image of Artemia=A0
>Credit: Matthew Ronshaugen, UCSD
>
>FIRST GENETIC EVIDENCE UNCOVERED OF HOW MAJOR CHANGES
>IN BODY SHAPES OCCURRED DURING EARLY ANIMAL EVOLUTION
>
>
>
>http://ucsdnews.ucsd.edu/newsrel/science/mchox.htm
>
>
>Biologists at the University of California, San Diego have uncovered the
>first genetic evidence that explains how large-scale alterations to body
>plans were accomplished during the early evolution of animals.
>
>In an advance online publication February 6 by Nature of a paper scheduled
>to appear in Nature, the scientists show how mutations in regulatory genes
>that guide the embryonic development of crustaceans and fruit flies allowed
>aquatic crustacean-like arthropods, with limbs on every segment of their
>bodies, to evolve 400 million years ago into a radically different body
>plan: the terrestrial six-legged insects.
>
>The achievement is a landmark in evolutionary biology, not only because it
>shows how new animal body plans could arise from a simple genetic mutation,
>but because it effectively answers a major criticism creationists had long
>leveled against evolution=8Bthe absence of a genetic mechanism that could
>permit animals to introduce radical new body designs.
>
>=B3The problem for a long time has been over this issue of macroevolution,=B2
>says William McGinnis, a professor in UCSD=B9s Division of Biology who headed
>the study. =B3How can evolution possibly introduce big changes into an
>animal=B9s body shape and still generate a living animal? Creationists have
>argued that any big jump would result in a dead animal that wouldn=B9t be abl=
>e
>to perpetuate itself. And until now, no one=B9s been able to demonstrate how
>you could do that at the genetic level with specific instructions in the
>genome.=B2
>
>The UCSD team, which included Matthew Ronshaugen and Nadine McGinnis, showe=
>d
>in its experiments that this could be accomplished with relatively simple
>mutations in a class of regulatory genes, known as Hox, that act as master
>switches by turning on and off other genes during embryonic development.
>Using laboratory fruit flies and a crustacean known as Artemia, or brine
>shrimp, the scientists showed how modifications in the Hox gene Ubx=8Bwhich
>suppresses 100 percent of the limb development in the thoracic region of
>fruit flies, but only 15 percent in Artemia=8Bwould have allowed the
>crustacean-like ancestors of Artemia, with limbs on every segment, to lose
>their hind legs and diverge 400 million years ago into the six-legged
>insects.
>
>
>
>=B3This kind of gene is one that turns on and off lots of other genes in orde=
>r
>to make complex structures,=B2 says Ronshaugen, a graduate student working in
>William McGinnis=B9 laboratory and the first author of the paper. =B3What we=B9ve
>done is to show that this change alters the way it turns on and off other
>genes. That=B9s due to the change in the way the protein produced by this gen=
>e
>functions.=B2
>
>=B3The change in the mutated protein allows it to turn off other genes,=B2 says
>William McGinnis, who discovered with two other scientists in 1983 that the
>same Hox genes in fruit flies that control the placement of the head, thora=
>x
>and abdomen during development are a generalized feature of all animals,
>including humans. =B3Before the evolution of insects, the Ubx protein didn't
>turn off genes required for leg formation. And during the early evolution o=
>f
>insects, this gene and the protein it encoded changed so that they now
>turned off those genes required to make legs, essentially removing those
>legs from what would be the abdomen in insects.=B2
>
>The UCSD team=B9s demonstration of how a mutation in the Ubx gene and changes
>in the corresponding Ubx protein can lead to such a major change in body
>design undercuts a primary argument creationists have used against the
>theory of evolution in debates and biology textbooks. Their specific
>objection to the idea of macroevolutionary change in animals is summed up i=
>n
>a disclaimer that the Oklahoma State Textbook Committee voted in November,
>1999 to include in that state=B9s biology textbooks:
>
>=B3The word evolution may refer to many types of change. Evolution describes
>changes that occur within a species. (White moths, for example, may evolve
>into gray moths). This process is microevolution, which can be observed and
>described as fact. Evolution may also refer to the change of one living
>thing into another, such as reptiles and birds. This process, called
>macroevolution, has never been observed and should be considered a theory.=B2
>
>=B3The creationists=B9 argument rests in part on the fact that animals have two
>sets of chromosomes and that in order to get big changes, you=B9d need to
>mutate the same genes in both sets of chromosomes,=B2 explains McGinnis. =B3It=B9=
>s
>incredibly unlikely that you would get mutations in the same gene in two
>chromosomes in a single organism. But in our particular case, the kind of
>mutation that=B9s in this gene is a so-called dominant mutation, so you only
>need to mutate one of the chromosomes to get a big change in body plan.=B2
>
>The discovery of this general mechanism for producing major leaps in
>evolutionary change has other implications for scientists. It may provide
>biologists with insights into the roles of other regulatory genes involved
>in more evolutionarily recent changes in body designs. In addition, the
>discovery in the UCSD study, which was financed by the National Institute o=
>f
>Child Health and Human Development, of how this particular Hox gene
>regulates limb development also may have an application in improving the
>understanding human disease and genetic deformities.
>
>=B3If you compare this gene to many other related genes, you can see that the=
>y
>share certain regions in their sequences, which suggests that their functio=
>n
>might be regulated like this gene,=B2 says Ronshaugen. =B3This may establish
>how, not only this gene, but relatives of this gene in many, many different
>organisms actually work. A lot of these genes are involved in the
>development of cancers and many different genetic abnormalities, such as
>syndactyly and polydactyly, and they may explain how some of these
>conditions came to be.=B2=A0
>
>
>Copyright =A92001 Regents of the University of California. All rights
>reserved.
>
>Official web page of the University of California, San Diego
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