Sex is sexy, biology is not

Here is proof yet again that sex sells, and that it sells really well.

A few days back there were a lot of headlines about a creature which has not had sex for the past 100 million years. The creatures are the bdelloid rotifers, microscopic aquatic organisms whom no biologist has ever caught having sex. They are believed to reproduce asexually by cloning.

But all this is old hat, so much so that even a mere reader of pop-biology books like me knows this stuff. So why the sudden headlines? There hangs an interesting story about human culture.

The journal PLoS Biology, which is part of the admirable project of providing open access to scientific research, has a system of publishing popular summaries of important articles. On 20th March it published a summary titled 'Who Needs Sex (or Males) Anyway?'. The press and most of the blogosphere picked up the title and the first paragraph which mentioned asexual reproduction in the rotifers and ran with it. And in doing so it missed the real essence of the article, which was to study the meaningfulness of the species concept when discussing asexually reproducing species. If there is no sex to mix up the gene pool in each generation, then is it meaningful to talk of an species as an evolutionary entity? The paper show that at least for these rotifers it is. And that whether you use a certain quantifiable feature of the rotifers bodies to do your classification or you use DNA sequences, you end up with the same 'species' categories. That is what the paper is really about. Asexuality of the rotifers is something it uses as an established premise. Yet, that is what the media really picked up.

The right kind of sex life may or may not make you long-lived, but it certainly makes you popular.

In defense of the "100 million years of chastity" headlines, the asexuality of bdelloid rotifers does pose an interesting problem for evolutionary biology. It is generally believed that sexual reproduction and the recombination of genes it brings about is necessary to allow a population of organisms to keep up with changes in its environment. This argument appears to be supported by evidence which shows that while in the course of evolution different organisms have developed asexual reproduction, this trait has not survived for long.

Bdelloid rotifers throw a spanner in this neat story. They appear to have survived for millions of years by reproducing asexually and hence suggest that sex may not be really necessary for survival.

However the real twist will come if someone discovers that the bdelloid rotifers do have sex after all. This has happened before. Some other organisms which were early thought to be asexual are now known to reproduce sexually—the males were so insignificant that they had earlier been mistaken as parasites feeding on the females. The females of some other species may concur.