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.
Thanks for the ping!
BTW that was not angels
Greek mythology) son of Daedalus; while escaping from Crete with his father (using the wings Daedalus had made) he flew too close to the sun and the wax melted and he fell into the Aegean and drowned
http://upload.wikimedia.org/wikipedia/commons/1/17/Landon-IcarusandDaedalus.jpg
Musta used an airbrush in the touchup then. :-)
Sorry! Couldn't resist.
No touching!
Wouldn't dream of it. LOL!
OMG! As soon as I take a short break, look what goes on!!!
It's best to forget it or I might have to bring out the heavy artillery. ;) LOL!
Very good explanation.
Fruit flies are in a taxonomic family (Drosophilidae) within the class Insecta. So you want something to "speciate" out of its whole family, not just out of its species, before you'll believe in speciation?
Ah! This would be the promising new science of Pig-Ignorantism now battering at schoolhouse doors all around the country. It could only be that.
You must be evolving..........considering this is a "evolution" thread........
Speaking about your food supply I think....
:-)
What about Bird Flu? Is the anxiety justified?
uh oh
yes...he's now trying to pass himself off as a youngster! : )
Gulp!
but, he's not as tricky as some wimmin I know....he can't fool us!
This has got to be the strangest crevo thread I have ever been on. LOL!
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.
