Some insects and roundworms pick up DNA from bacteria living within their cells, new research shows.
The DNA transfer occurs in the animals' egg cells, so the genetic modification passes between generations. The mechanism therefore provides an alternative to mutation of existing DNA as a way for the species to acquire new genetic traits.
Gene swapping is ubiquitous among bacteria and other single-celled organisms. Even plants and fungi are known to occasionally adopt a piece of foreign DNA. But scientists thought that multicellular animals picked up genes from bacteria only rarely.
"Our data are indicating that [DNA transfer] is going on all the time," says John H. Werren of the University of Rochester in New York, who led the research team.