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.
not my fault!
if you say so
You want my dissertation now, or later?
I wouldn't know about turnips. : )
And no slinking off..........
I needed an alter ego for you quickly and couldn't think :)
I thought that a virus is not considered to be a living thing, but something more like a naturally-occuring nanorobot.
thanks for getting my back!!! : )
Hmmm... have to ponder that. The evolution of mutant flying shark revolutions. You mean revolutions around the sun, or the revolution of flight?
if there were revolutions around the sun...I'd think the finned one would get more burned than tanned! : )
Freudian slip.........bad form on an evo thread......need better links to turnip speciation.
That means the registration of your flying shark pedigree.
Dang. Just like an AE..........
Viruses are kind of on the edge of the definition of life. But they do many things that living things do, so whether they count as life or chemical things might be an arbitrary decision.
Yellow root veggies shouldn't make comments about tanning.
but my tan is golden. : )
*Checking in wallet for registration*
Dang. Left it at home.
Wait, wait.......it's the third week in November in upstate NY as well, right?
What can this mean about golden tans?
Must link large article in the future for proof
Are you actually trying to insert some rationality into this thread? Now?
Good luck! ROFL!
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