New animal model developed from ancient cells

Scientists at the University of Chicago have created the first genetically modified animals containing reconstructed ancient genes, which they used to test the evolutionary effects of genetic changes that happened in the deep past on the animals’ biology and fitness.

The research, published early online in Nature Ecology & Evolution on Jan. 13, is a major step forward for efforts to study the genetic basis of adaptation and evolution. The specific findings, involving the fruit fly’s ability to break down alcohol in rotting fruit, overturn a widely-held hypothesis about the molecular causes of one of evolutionary biology's classic cases of adaptation.

Until recently, most studies of molecular adaptation have analyzed gene sequences to identify "signatures of selection" patterns suggesting that a gene changed so quickly during its evolution that selection is likely to have been the cause. The evidence from this approach is only circumstantial, however, because genes can evolve quickly for many reasons, such as chance, fluctuations in population size, or selection for functions unrelated to the environmental conditions to which the organism is thought to have adapted.