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There’s a reason why so many animals go through the rigmarole of sexual reproduction, as when two genotypes become one it brings with it a welcome boost of genetic variation. Such variation can be crucial for the survival of a species, enabling them to overcome change better than a population confined by very little in the way of genetic wiggle room. For this reason, it was thought that asexually reproducing species were doomed to a dead-end fate – but new research has discovered a beetle that’s endured without bonking for millions of years.
Published in the journal PNAS, the study focused on the beetle mite species Oppiella nova. They gathered up specimens from a range of populations as well as some members of the closely related species Oppiella subpectinata. What separates the two groups of beetle mites is that O. nova was thought to reproduce asexually while O. subpectinata is known to get it on instead.
They then sequenced their genomes to search for what’s known as the Meselson effect, evidence for a species that reproduces exclusively through asexual means. If found, it would prove that O. nova - a species of beetle mite made up entirely of females - truly have survived for millions of years without the need for sexual reproduction.
Finding it involves analyzing genetic code for evidence of prolonged asexual genetic recombination. The result is two genome copies within one individual that have independently accumulated mutations. This causes them to become increasingly disparate over time, eventually evolving independently of one another.
“That may sound simple,” said Professor Tanja Schwander from the Department of Ecology and Evolution of the University of Lausanne in a statement. “But in practice, the Meselson effect has never been conclusively demonstrated in animals – until now.”
Sure enough, the Meselson Effect was present in O. nova and not O. subpectinata. The researchers say this constitutes the first time the effect has been demonstrated in an animal, and that it proves O. nova, nicknamed “ancient asexual scandals” (band name, anyone?), really have survived without the need for sex.
“Our results clearly show that O. nova reproduces exclusively asexually,” said Dr Jens Bast, Emmy Noether junior research group leader at the University of Cologne’s Institute of Zoology. “When it comes to understanding how evolution works without sex, these beetle mites could still provide a surprise or two.”
Evidently, surviving millennia without getting your rocks off is, while rare, actually possible. So, what keeps beetle mites going after all these sexless years? The research team will now try to find out.
