CAMBRIDGE, Mass. -- Long viewed as straitlaced spinsters, sexless freshwater invertebrate animals known as bdelloid rotifers may actually be far more promiscuous than anyone had imagined: Scientists at Harvard University have found that the genomes of these common creatures are chock-full of DNA from plants, fungi, bacteria, and animals.
The finding, described this week in the journal Science, could take the sex out of sexual reproduction, showing that bdelloid rotifers, all of which are female, can exchange genetic material via other means.
"Our result shows that genes can enter the genomes of bdelloid rotifers in a manner fundamentally different from that which, in other animals, results from the mating of males and females," says Matthew S. Meselson, Thomas Dudley Cabot Professor of the Natural Sciences in Harvard's Faculty of Arts and Sciences.
In essence, Meselson and colleagues say, bdelloids may acquire DNA by habitually disintegrating their genomes -- something these unusual animals do regularly during periods of desiccation, which fractures their genetic material and ruptures cellular membranes. Miraculously, bdelloids can then spring back to life upon rehydration of their habitats, readily reconstituting their genomes and their membranes.
In the process of rebuilding their shattered DNA, though, they may adopt shreds of genetic material from other bdelloids in the same puddle, as well as from unrelated species.
Meselson and co-authors Eugene A. Gladyshev and Irina R. Arkhipova believe the findings may solve the longstanding mystery of bdelloids' sexless ways, and may shed light on their ability to adapt to new environments.
"These fascinating animals not only have relaxed the barriers to incorporation of foreign genetic material, but, more surprisingly, they even managed to keep some of these alien genes functional," says Arkhipova, a staff scientist in Harvard's Department of Molecular and Cell
|Contact: Steve Bradt|