No sex for 40 mln years? No problem for 1 organism

By Michael Kahn

LONDON (Reuters) - One microscopic organism has thrived despite remaining celibate for tens of millions of years thanks to a neat evolutionary trick, researchers said.

Asexual reproduction has allowed duplicate gene copies of the single-celled creatures -- called bdelloid rotifers -- to become different over time.

This gives the rotifers a wider pool of genes to help them adapt and survive, the researchers said in the journal Science.

"It is like having a bigger tool kit," Alan Tunnacliffe, a molecular biologist at the University of Cambridge, said in a telephone interview. "You can do the same job but better."

Other researchers had shown the translucent, waterborne creatures could survive for 40 million years without sexual relations.

The question, Tunnacliffe said, was how the creatures found in pools of water accomplished this feat without the gene-swapping made possible by sexual reproduction.

"Sexual reproduction is supposed to be a good thing in evolution," he said on Thursday.

"So when you come across an organism like the bdelloid, which hasn't engaged in sexual reproduction for tens of millions of years, you begin to question why sex is important."