MBL, WOODS HOLE, MA Where do you get your genes?
If you are an animal, you inherit them from your parents at the moment of conception, and that's about it. No later incorporation of environmental DNA for you, unless you become host to a parasite or an endosymbiont that somehow transfers bits of its genome into yours (which is a rarely documented event).
Unless you are a bdelloid rotifer, that is.
This odd, microscopic, freshwater animal is making news once again, this time for the startling discovery of numerous chunks of foreign DNA in its genome. In a paper published this week in Science, evidence for massive horizontal gene transferfrom bacteria, fungi, even from plantsinto the bdelloid rotifer genome is presented by Irina Arkhipova and Matthew Meselson, scientists at the MBL's Josephine Bay Paul Center and at Harvard University, and Harvard graduate student Eugene Gladyshev.
While horizontal gene transfer is common in bacterial species, it was unheard of in the animal kingdom on such a massive scale until this study.
"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 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," she says.
This finding 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 offspringconfers diversity and greater adaptability on a population, thereby boosting its evolutionary success. Arkhipova's study suggests that if bdelloids can incorporate for
|Contact: Diana Kenney|
Marine Biological Laboratory