Vi afviger mere fra vores nærmeste evolutionære slægtninge end hidtil antaget. Det viser en ny undersøgelse, der kaster lys over, hvordan vi som art har en specielt evne til hurtig evolution.

It's often said that there's only 1% to 2% difference between the genomes of chimps and humans, two species that had their most recent common ancestor about 5 million years ago. But that percentage refers to the nucleotide differences in shared genes. Evolution can do more than just tinker with gene sequences; the number of copies of a gene can also vary from one species to the next, even when the gene itself stays the same. Sometimes genes are gained, and sometimes they are lost. Quantifying this turnover has been difficult, however, because it requires the complete genome sequences of many species.

Now, with several mammals sequenced and a suite of new statistical methods available, Matthew Hahn and colleagues at Indiana University, Bloomington, have taken a closer look. They measured how quickly genes were duplicated or lost across six mammalian genomes. By looking at about 120,000 genes in 10,000 gene families, they discovered that gene turnover was faster in primates than in dogs or in rodents, and even faster in humans, who swapped genes 1.6 times faster than monkeys and 2.8 times quicker than nonprimates. Thanks to this rapid change, 6.4% of the 22,000-odd human genes aren't present in chimps, making the gap between the two suddenly seem much wider.

http://sciencenow.sciencemag.org...