Posted on 11/20/2005 9:27:40 AM PST by restornu
Scientists at the University of Arizona may have witnessed the birth of a new species. Biologists Laura Reed and Prof Therese Markow made the discovery by observing breeding patterns of fruit flies that live on rotting cacti in deserts.
The work could help scientists identify the genetic changes that lead one species to evolve into two species.
The research is published in the Proceedings of the National Academy of Sciences.
One becomes two
Whether the two closely related fruit fly populations the scientists studied - Drosophila mojavensis and Drosophila arizonae - represent one species or two is still debated by biologists.
However, the University of Arizona researchers believe the insects are in the early stages of diverging into separate species.
The emergence of a new species - speciation - occurs when distinct populations of a species stop reproducing with one another.
When the two groups can no longer interbreed, they cease exchanging genes and eventually go their own evolutionary ways becoming separate species. Though speciation is a crucial element of understanding how evolution works, biologists have not been able to discover the factors that initiate the process.
In fruit flies there are several examples of mutant genes that prevent different species from breeding but scientists do not know if they are the cause or just a consequence of speciation.
Sterile males
In the wild, Drosophila mojavensis and Drosophila arizonae rarely, if ever, interbreed - even though their geographical ranges overlap.
In the lab, researchers can coax successful breeding but there are complications.
Drosophila mojavensi s mothers typically produce healthy offspring after mating with Drosophila arizonae males, but when Drosophila arizonae females mate with Drosphila mojavensis males, the resulting males are sterile.
Laura Reed maintains that such limited capacity for interbreeding indicates that the two groups are on the verge of becoming completely separate species.
Another finding that adds support to that idea is that in a strain of Drosophila mojavensis from southern California's Catalina Island, mothers always produce sterile males when mated with Drosophila arizonae males.
Because the hybrid male's sterility depends on the mother's genes, the researchers say the genetic change must be recent.
Reed has also discovered that only about half the females in the Catalina Island population had the gene (or genes) that confer sterility in the hybrid male offspring.
However, when she looked at the Drosophila mojavensi s females from other geographic regions, she found that a small fraction of those populations also exhibited the hybrid male sterility.
The newly begun Drosophila mojavensis genome sequencing project, which will provide a complete roadmap of every gene in the species, will help scientists pin down which genes are involved in speciation.
"First rule of holes:
Stop digging.
You are really sounding foolish and like a truly nasty piece of work, far from the detached science expert you feign to be."
Second rule of holes. Don't try to talk about things you are not willing to defend.
BTW, I never pretended to be an expert. I DO expect people who make statements to be willing to back then up.
Somebody can't make up their mind:
"Mind your own business."
http://www.freerepublic.com/focus/f-chat/1525629/posts?page=273#273
"This is an open forum and people are allowed to post about whatever is posted."
http://www.freerepublic.com/focus/f-chat/1525629/posts?page=285#285
"Mind your own business."
http://www.freerepublic.com/focus/f-chat/1525629/posts?page=298#298
She is lovely
Stop acting like a silly ass.
Is this so hard to understand?
And you still haven't posted anything I've said about what I SPECIFICALLY BELIEVE ABOUT EVOLUTION.
Lakeshark knows what I specifically believe about evolution, because I told him. Lakeshark, do you see what I told you on this thread.............anywhere?
I meant to ping you to my post #305
Somebody can't make up their mind:
"Mind your own business."
http://www.freerepublic.com/focus/f-chat/1525629/posts?page=273#273
"This is an open forum and people are allowed to post about whatever is posted."
http://www.freerepublic.com/focus/f-chat/1525629/posts?page=285#285
"Mind your own business."
http://www.freerepublic.com/focus/f-chat/1525629/posts?page=298#298
Carguit, you're the one in over your head.
you contradicted yourself and you're not getting the hint.
hint: in a dictionary, besides the word man, how you act is not in the definition.
DING DING DING DING DING It took that long for you to finally admit that I wasn't lying about that?
"Mind your own business."
http://www.freerepublic.com/focus/f-chat/1525629/posts?page=273#273
"This is an open forum and people are allowed to post about whatever is posted."
http://www.freerepublic.com/focus/f-chat/1525629/posts?page=285#285
"Mind your own business."
http://www.freerepublic.com/focus/f-chat/1525629/posts?page=298#298
Make up your mind, and buy a clue.
"Is that your response to your inability to defend your statements?"
You evidently missed that she does believe in evolution.
You are SO bent on fighting with somebody that you've missed what was said to you.
How about you fix your contradiction:
"Mind your own business."
http://www.freerepublic.com/focus/f-chat/1525629/posts?page=273#273
"This is an open forum and people are allowed to post about whatever is posted."
http://www.freerepublic.com/focus/f-chat/1525629/posts?page=285#285
"Mind your own business."
http://www.freerepublic.com/focus/f-chat/1525629/posts?page=298#298
First of all, I am not a liar. Secondly, I never said "scientists who question evolution are not allowed to publish." You said that.
"In effect, YOU have backed up the reason why I won't post what I specifically believe about evolution." You have posted this; why are you so scared to restate it? Duh, I posted that. Scared to restate what? Why I won't post what I specifically believe about evolution? I'm not scared...I've said it at least a half a dozen times: you're obnoxious, as are most who post on these threads. Remember me saying that, over and over again? That's being scared, repeating myself a hundred times?
" And you still haven't posted anything I've said about what I SPECIFICALLY BELIEVE ABOUT EVOLUTION." You said it is all theory and speculation. That nobody was there. Then you said that anti-evolution scientists aren't allowed to publish. Are you backing away from this?
I didn't say that "anti-evolution scientists aren't allowed to publish." You did.
I did say NOBODY WAS THERE. I'm not backing away from that. Unless you're now going to claim you were. I did say it's theory. Are you going to claim it's fact? I was always taught evolution was a theory, not fact. And what, specifically, did I say I believe about evolution? Nothing, to you.
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