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.
Though God all things are possible!
Some call it evolution...
others view it in terms of "A Work In Progress" when one door closes another one Opens!
Just to level set, what is the definition of "species"?
If its highly likely that fruit flies live in rotten fruit and just hatch, then why do I feel like rotten fruit sometimes with the fruit flies I attract? Drum roll..... LOL (Sorry I couldn't resist that one)
lol! (I'm not going to answer that one!!!! : )
Wake me up when the fruit flies speciate into something else besides other fruit flies.
Yes, dear, there is no Santa Claus.
You'll encounter more than one definition. It's a tad fuzzy because all creatures form a continuum, so where you draw the line between closely-related species can seem arbitrary. Usually, the line is drawn where the two versions don't interbreed, at least not often or successfully, but there are exceptions to that.
As time goes on, and the two groups mutate in isolation, it becomes increasingly obvious where the line should be drawn. It's even more obvious if the intermediate stages no longer exist. But sometimes it's a tough call. This seems to be because the development of new species is an ongoing process.
Great. Thank you. That makes a lot of sense.
That fly turned into that women? woa
We need to get nully take
http://www.freerepublic.com/focus/f-chat/1525629/posts?page=24#24
Some people just prefer to use alarm clocks
But it is a hopeless endeavour to decide this point, until some definition of the term "species" is generally accepted; and the definition must not include an indeterminate element such as an act of creation. We might as well attempt without any definition to decide whether a certain number of houses should be called a village, town, or city. We have a practical illustration of the difficulty in the never-ending doubts whether many closely-allied mammals, birds, insects, and plants, which represent each other respectively in North America and Europe, should be ranked as species or geographical races; and the like holds true of the productions of many islands situated at some little distance from the nearest continent.Descent of Man, Chapter 7.
Not going there.
Wise man.
Close your eyes and go to sleep.
Might not let you forget that one....
:-)
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