Sharing = Evolution

Researchers have long known that bacteria and archaea can alter, lose, or duplicate their genes almost at will in order to survive in a range of environments, says Scientific American's Carrie Arnold. While it's also known that bacteria can also acquire genes from their neighbors — a trait that can lead to antibiotic resistance — it was thought that this kind of horizontal gene transfer was rare and occurred only under strong environmental pressures, Arnold says. However, a new study recently published in PLoS Genetics shows that horizontal gene transfer happens often and can even happen between prokaryotes of different species. The study's authors calculate that the prokaryotes they studied acquired between 88 and 98 percent of new genes through horizontal transfer," Arnold says. The transfer allows the prokaryotes to establish themselves in new environments, and the study's authors tell Arnold their work shows that horizontal gene transfer is the dominant force behind the evolution of prokaryotes.