"Massive" Horizontal Gene Transfer In Animal Kingdom Revealed
If you're an animal, you inherit your genes from your parents at the moment of conception, right? Not quite, according to scientists from the Woods Hole Marine Biological Laboratory (MBL), who have uncovered evidence of "massive" horizontal gene transfer in the animal known as the bdelloid rotifer. Reporting their findings in Science, the researchers say they have discovered numerous chunks of foreign DNA in its genome, from bacteria, fungi, and even from plants. Gene transfer on such a large scale was, until now, thought impossible in the animal kingdom.
"It is quite amazing that bdelloids are able to recruit foreign genes, which were acquired from remarkably diverse sources, to function in the new host," says MBL's Irina Arkhipova. "Bdelloids may have the capacity for tapping into the entire environmental gene pool, which may be of [evolutionarily] adaptive significance during expansion into new ecological niches, and may even contribute to bdelloid speciation."
The new findings may help to explain why bdelloids, which are exclusively asexual, have managed to diversify into more than 360 species over 40 million years of evolution. Sometimes called an "evolutionary scandal," bdelloids contradict the notion that sex - which recombines the DNA from the parents in their offspring - confers diversity and greater adaptability on a population, thereby boosting its evolutionary success. Arkhipova's study suggests that if bdelloids can incorporate foreign DNA from their environment, they could also pick up DNA from other bdelloids which, from an evolutionary standpoint, is almost as good as having sex.