This led Moran and Jarvik to hypothesize that somehow the aphids acquired genes for making carotenoids from another species, presumably bacteria. They thus compared the aphid carotenoid genes to those from other species in the genome databank. And they got a surprise. Yes, the aphid genes did come from another species, but not a bacterial one. They were closely related, instead, to genes from fungi.

Moran and Jarvik also showed that the red-versus-green polymorphism is based on a mutation that presumably happened after the genes were captured: green aphids derive from a “mutation” in one of the carotenoid desaturase genes, a mutation that deleted about 30,000 base pairs of the DNA. Presumably the red color was ancestral, and the green resulted from an error in DNA replication. (Moran and Jarvik also studied a mutation from red to green that spontaneously arose in the lab, and found that the new green form was based on a single amino-acid change, from glutamic acid to lysine, in the same carotenoid desaturase gene.)

This is a remarkable use of an acquired gene in an adaptive way, for the captured fungus DNA is the basis for the color polymorphism presumably maintained by natural selection. It’s clear, then, that evolution in one species can be based on the acquisition of genetic information from a distantly related species. Now that different species’ genomes can be sequenced quickly and reasonably cheaply, we’re bound to find more cases like this. I don’t think they’ll be that common, simply because we don’t see evidence of LGT from existing gene trees in animals and plants. Nevertheless, Moran and Jarvik have shown that nature still has the capacity to surprise us. And a good thing, too, because it makes our jobs as evolutionary biologists even more interesting.

Tyrannical wrote:Aphids nab pigment genes from fungus

Lateral Gene Transfer sure is interesting. They are probably right that it is very rare though
Though how often do we really look for it? Only when it is really obvious?



http://whyevolutionistrue.wordpress.com/2010/05/01/aphids-nab-pigment-genes-from-fungus/

This led Moran and Jarvik to hypothesize that somehow the aphids acquired genes for making carotenoids from another species, presumably bacteria. They thus compared the aphid carotenoid genes to those from other species in the genome databank. And they got a surprise. Yes, the aphid genes did come from another species, but not a bacterial one. They were closely related, instead, to genes from fungi.

Moran and Jarvik also showed that the red-versus-green polymorphism is based on a mutation that presumably happened after the genes were captured: green aphids derive from a “mutation” in one of the carotenoid desaturase genes, a mutation that deleted about 30,000 base pairs of the DNA. Presumably the red color was ancestral, and the green resulted from an error in DNA replication. (Moran and Jarvik also studied a mutation from red to green that spontaneously arose in the lab, and found that the new green form was based on a single amino-acid change, from glutamic acid to lysine, in the same carotenoid desaturase gene.)

This is a remarkable use of an acquired gene in an adaptive way, for the captured fungus DNA is the basis for the color polymorphism presumably maintained by natural selection. It’s clear, then, that evolution in one species can be based on the acquisition of genetic information from a distantly related species. Now that different species’ genomes can be sequenced quickly and reasonably cheaply, we’re bound to find more cases like this. I don’t think they’ll be that common, simply because we don’t see evidence of LGT from existing gene trees in animals and plants. Nevertheless, Moran and Jarvik have shown that nature still has the capacity to surprise us. And a good thing, too, because it makes our jobs as evolutionary biologists even more interesting.