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.
Really? Must be? Why? Please explain.
Is it possible all religions are just different manifestations of worship of the same god-force? Believers of one religion won't agree but I think from a truly neutral position one has to agree this is possible. If there is only one true religion then all faiths but one are false. If there is no god or basis for religion then all religions are false.
Thus the only fantasy world is that constructed by the members of those false faiths.
True, but determining the false faiths is the crux of the biscuit (to quote Frank Zappa)
Are the Buddhists the false faith?
Are the Mormons the false faith?
Are the Baha’i’s the false faith?
Are the Evolutionists the false faith?
So many questions, so few definitive answers.
Should you have rather said....
...it's belief in something that I have not seen....?
I like your statement of Santa, for I think it is a destroyer of faith:
What? No Tooth Fairy!!
..and Santa is a lie!?!?
..and NOW you want me to believe in a 'GOD' I cannot see either?!
Think about it Christians, as you lie to your young children this season, just so you can see the 'look on their little faces'......
Please... try some OTHER way to 'make them be good' for a month!
There seems to be more evidence for creation when it come to the creation of the universe (big bang) and the creation of life ***but there seems to be more evidence for evolution related to the creation of man.that would appear in the 'record'.
(Talk about a chicken or the egg question!)
How come this never happened in nature to fruit flies? In theory considering their life span and reproductive capabilities we should have billions upon billions of species of fruit flies by now shouldn't we?
I don't know what point you're trying to make, or how you compute "billions upon billions," but we do have a large number of them:
There are some 120,000 species known, including the most common 'pet': the Common House Fly. Many more species still fly about undiscovered. Some experts believe that there may be well over 1 million species.Source: Introduction to flies and Mosquitoes (Diptera).
I'm not trying to sell you on God. You keep bringing that up.
What skin is it off of your teeth if someone else does. I'm asking why you are so passionate about trying to knowingly destroy someone elses faith, and collapsing their world.
"I want to believe that there is some "good" end in Life"
Life itself is good, and far more than we deserve.
After food, shelter, & clothing; happiness is just a decision we make. Unless you are starving, frozen, or running around naked; you are disappointed because you want to be.
Why is it imperative, to you, that everyone else shares your disappointment. On the face of it, it seems the height of selfishness. Please correct me on this.
To what end do you weaken another man's faith?
Choosing is a decision.
Happiness is something you choose, or not choose. Others have chosen happiness. Why does that upset you?
To what end do you weaken another man's faith?
If I choose to believe the sky is green, what difference does it make to you?
Do you wish to have control over what I tell my children?
To what end do weaken another man's faith?
I congratulate you. You are an exception. However, you're the first person I've seen who admits to being both a creationist and an ID'er. You are truly exceptional.
And yet Christianity is the only faith that has resulted in a culture that values freedom and is wealthy enough to have held it for over 200 years.
No other faith is even close.
My spider sense is tingling.
What?
Didn't the poster of #105 recognize, & even compliment the existance of genes?
Where might I find these God-believers that deny the existance of genes, which you have frequently mentioned?
To what end do you weaken another mans faith? What difference is it to you if someone else believes in a god?
Check your cell phone.
Since we are given free-will, some of us will choose just about anything as our reason to live and behave. I choose God. People will tend to follow the example of someone who lives well, so I don't spend a lot of time trying to convince anyone what they should believe.
As to the issue of genes, I don't believe you're serious. When someone refers to species as "kinds" that are identical even when they can't cross-breed, then says they reproduce accurately, when they clearly don't and genetic diseases abound, then they clearly have no use or understanding of genes, or as I like to say, they don't believe in genes since they ignore their purpose and function.
That this isn't obvious to you convinces me that you're not seriously interested.
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