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Changing One Gene Launches New Fly Species
Science Daily ^ | 08 December 2003 | Staff

Posted on 12/09/2003 7:47:21 AM PST by PatrickHenry

In what has been described as the "perfect experiment," evolutionary biologists at the University of Chicago replaced a single gene in fruit flies and discovered a mechanism by which two different "races" begin to become different species, with one group adapted to life in the tropics and the other suited to cooler climates. The tropical group was more tolerant of starvation but less tolerant of cold. The temperate group was less able to resist starvation but better adapted to cool weather.

The altered gene also changed the flies' pheromones, chemical signals that influence mating behavior. As a result, the researchers show in the Dec. 5 issue of Science, the two groups of flies are not only fit for different environments but may also be on their way to sexual isolation, a crucial divide in the emergence of a new species.

"This study directly connects genetics with evolution," said Chung-I Wu, Ph.D., professor and chairman of ecology and evolution at the University of Chicago and director of the study. For the first time, we were able to demonstrate the vast importance in an evolutionary context of a small genetic change that has already occurred in nature."

"We had the luxury," added co-author Tony Greenberg, Ph.D., a postdoctoral student in Wu's laboratory, "of watching the essential event in Darwinian evolution, the first step in the origin of a new species. We were quite impressed, that this simple alteration played such a dramatic role, both adapting flies to a new environment and changing their sex appeal. Once two groups become sexually isolated, there's no turning back."

The scientists used a new technique to knock out one gene from fruit flies and then replace it with one of two slightly different versions of the same gene.

They focused on a gene called desaturase2 that plays a role in fat metabolism. Flies from Africa and the Caribbean, where there is tremendous competition for food but cold temperatures are not a problem, have one version of ds2. Flies from cooler climates, where there is less competition for food but greater temperature variation, have a smaller, inactive version of ds2.

The same gene plays a role in the production of cuticular hydrocarbons -- waxy, aromatic compounds that coat the abdomen of female flies. A male fly, in a romantic mood, strokes the female's abdomen with his feet, which have sensors that recognize specific hydrocarbons, like a perfume.

In a previous report, Wu's laboratory found most males with the temperate version of the ds2 gene preferred females with the same gene; tropical males preferred tropical females.

"Developing increased cold tolerance was an important step for flies that migrated out of Africa to Europe and Asia," Wu said. The change in pheromones, which altered patterns of sexual attraction, "was a by-product of adaptation to colder weather."

Fruit flies have a migratory history similar to humans. They originated in Africa, spread to Europe and Asia and went on to populate the world. As with humans, there is greater diversity within African flies than between flies from Africa and other continents.

Although fruit flies have been a favorite model for the study of genetics since the early 20th century, recognition of consistent differences between tropical and temperate flies came only in 1995. The discovery, however, "has allowed a lot of analysis of the evolution of adaptive traits," Wu said.

"But this was the first time we have been able to study the process from the very beginning," he added, "to watch the first steps as one species begins to split into two, then seals the bargain by increasing sexual isolation. This is the essence of biodiversity."

Additional authors include Jennifer Moran from the Wu lab and Jerry Coyne of the University of Chicago. The National Institutes of Health and the National Science Foundation funded the study.


TOPICS: Culture/Society; Miscellaneous; Philosophy
KEYWORDS: crevolist; evolution; genetics; speciation
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To: PatrickHenry
We were quite impressed, that this simple alteration played such a dramatic role, both adapting flies to a new environment and changing their sex appeal.
I suddenly found my self more attracted to brunettes than blonds shortly after I moved from Kansas to Georgia. I wonder if I was the victim of a genetic experiment gone awry.
21 posted on 12/09/2003 9:10:22 AM PST by avg_freeper (Gunga galunga. Gunga, gunga galunga)
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To: PatrickHenry
Specation observed.

Well, I don't think you will find ONE SINGLE creationist or Intelligent Design backer that does not believe that DNA contains the blueprint for every life form on this planet.

They replaced a gene to create a different blueprint. If they replaced enough of them, I am sure that you could come up with a fruitfly with a snake's body having banana's sticking out of it's arse.

The point is this was done MANUALLY, It was NOT observed naturally, and there most definitely was intelligence behind the creation of a different blueprint.

When man starts to take on the role of God, it won't matter how smart we think we are or how much we think we know about the origin of life, because ours will be shortened.

22 posted on 12/09/2003 9:13:04 AM PST by ImaGraftedBranch (Education starts in the home. Education stops in the public schools)
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To: PatrickHenry
Great... this is the stuff I worry about... People tweaking genes. Tweak a gene create a new bug, tweak another create a new virus, I like progress and the options this science has .... but face it we as a people aren't all that bright. How much tweaking does it to take to do serious damage.

Damn near 50% of the people voted for Gore.
23 posted on 12/09/2003 9:16:37 AM PST by mike_9958
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To: PatrickHenry
It just proves the intelligent designer theory because this would never have happened accidentially. Genes just don't randomly swap around. There is a very elaborate process by which genes repair themselves to their original state. A deliberate laboratory forced change does NOT equal natural change.

BTW, how would more less resistance to starvation and more resistance to cooler weather make it more likely to survive? Cooler climates typically have LESS food available during parts of the year.
24 posted on 12/09/2003 9:19:17 AM PST by Blood of Tyrants (Even if the government took all your earnings, you wouldn’t be, in its eyes, a slave.)
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To: pepsi_junkie
I'm glad I'm not the guy who gets to see if the two different sets of flies can or can't make little flies together. Now, there's a job.
25 posted on 12/09/2003 9:21:43 AM PST by mewzilla
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To: mike_9958
I'm sitting here wondering if the new fly looks anything like that guy in the movie...
26 posted on 12/09/2003 9:23:24 AM PST by Judith Anne (Send a message to the Democrat traitors--ROCKEFELLER MUST RESIGN!)
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To: Judith Anne
Help me, help me!!!
27 posted on 12/09/2003 9:25:47 AM PST by mewzilla
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To: PatrickHenry
Gee, I wonder how much study it took for these educated idiots to discover that changing a gene changes a critter.
I guess there is a reason for mating after all, huh. Speciation my butt.
28 posted on 12/09/2003 9:28:00 AM PST by Havoc (If you can't be frank all the time are you lying the rest of the time?)
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To: pepsi_junkie
This proved that a small genetic change (somehow occurring, either by direct intervenion or perhaps by random mutation) will change the characteristics within a species. As far as I can tell, they may still interbreed. Even the scientists hedge by saying they have seen the first step in the proces of speciation only. Progress indeed. But for it to lead somewhere, they need to prove that eventually they can create different species altogether (i.e. unable to interbreed).

There you go, confusing the Darwinists with the facts.

29 posted on 12/09/2003 9:28:33 AM PST by Phaedrus
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To: mewzilla
Where DID that flyswatter go...?
30 posted on 12/09/2003 9:29:37 AM PST by Judith Anne (Send a message to the Democrat traitors--ROCKEFELLER MUST RESIGN!)
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To: PatrickHenry
Maybe something is wrong with the software. This thread appeared in the "NEWS/ACTIVISM" topics.
31 posted on 12/09/2003 9:29:50 AM PST by Protagoras (Vote Republican, we're not as bad as the other guys.)
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To: Phaedrus
Why wouldn't Darwinists make the same point you just did?
32 posted on 12/09/2003 9:29:53 AM PST by mewzilla
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To: Judith Anne
Hee hee. Need a flyswatter? Click here.
33 posted on 12/09/2003 9:33:25 AM PST by mewzilla
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To: mewzilla
EIGHT NINETY FIVE FOR A FRIKKEN FLYSWATTER!

Dang!
34 posted on 12/09/2003 9:35:30 AM PST by Judith Anne (Send a message to the Democrat traitors--ROCKEFELLER MUST RESIGN!)
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To: mewzilla
Incidently, there has been research on fruit flies since I was in high school (shortly after the great flood, I think).

They've been producing mutated flies with everything from acid to X-rays in the little buggers because they're apparently easy to work with, have been the subject of no focus groups, and haven't been lawyered up for reparations.

Seriously, PETA doesn't even care. How low can a fly get?

;-D
35 posted on 12/09/2003 9:40:19 AM PST by Judith Anne (Send a message to the Democrat traitors--ROCKEFELLER MUST RESIGN!)
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To: Judith Anne
LOL. But they're French flyswatters, don'cha know. Tres chic.

And on a related note, how does one tell the boy flies from the girl flies? If they don't interbreed, how do they know they just don't have a batch of flies of the same gender?

36 posted on 12/09/2003 9:43:19 AM PST by mewzilla
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To: mewzilla
And on a related note, how does one tell the boy flies from the girl flies? If they don't interbreed, how do they know they just don't have a batch of flies of the same gender?

Same way you find mothballs. See, there are these little tiny tweezers that hold their little legs....

37 posted on 12/09/2003 9:47:06 AM PST by Judith Anne (Send a message to the Democrat traitors--ROCKEFELLER MUST RESIGN!)
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To: PatrickHenry
Thanks for the ping!
38 posted on 12/09/2003 10:04:22 AM PST by Alamo-Girl
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To: ImaGraftedBranch
The point is this was done MANUALLY, It was NOT observed naturally, and there most definitely was intelligence behind the creation of a different blueprint.

This experiment wasn't designed to demonstrate the presence of a designer. It identifies a direct genetic contribution to a speciation event. The results confirm theoretical predictions.

If there was an experiment that demonstrated the presence of a designer, say, something elegant, like the double-slit light experiment, would you discount the results because it was done manually?

39 posted on 12/09/2003 10:05:23 AM PST by Nebullis
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To: mewzilla
If they don't interbreed, how do they know they just don't have a batch of flies of the same gender?

(There are no stupid questions!)

They're very easy to tell apart. Size, stripes, and sex combs. No tweezers necessary.

40 posted on 12/09/2003 10:09:02 AM PST by Nebullis
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