Last week, researchers at UC Irvine published a study in Nature that seemed to confirm the evolutionary theory that the exploitation of small differences in many different genes were responsible for new traits in fruit flies, rather that a large mutation in one single genes. Evolutionary theorists have argued over this point for many years, says the New York Times' Nicholas Wade, but it wasn't until this study came out that the so-called "soft sweep" theory of evolution really had any traction in the scientific community. In sequencing the genomes of the generations of fruit flies that they bred, the researchers were able to conclude that the "soft sweep" was responsible for the evolution they saw in the subsequent generations of fruit flies in the experiment, Wade says. "No single gene had swept through the population to effect the change; rather, the alternative versions of a large number of genes had become slightly more common," he says. But the implications of this research go beyond theories of evolution. "If complex traits, including susceptibility to disease, are influenced by just a few genes, then it should be easy to develop treatments that target the few genes' products," Wade says. "But if tens or hundreds of genes are involved in each trait, the task may be close to impossible." If "soft sweeps" are responsible for the way human genes work, then treatments targeted to single genes won't be very effective. Pharmaceutical companies might have to rethink their strategies for drug development, taking into consideration the total effect many genes can have on the development of the human genome.
Evolution of a Fruit Fly, Evolution of a Human
Sep 22, 2010