Natural selection influences genes to limit diversity

CAMBRIDGE, England, May 16 (UPI) -- There's now more evidence that the process of natural selection reduces genetic diversity.

When researchers looked at the genetic influence of evolutionary adaptations in tropical butterflies, they found beneficial mutations affect a series of unrelated genes. These genetic links, along with the genetic adaptation, are passed along to the offspring, despite the fact that they have no influence on the species' ability to survive.

By expanding its genetic influence, an adaptive mutation works to limit genetic diversity in each butterfly population.

Scientists have long been puzzled by the fact that larger species populations -- like those of humans and horseflies, for example -- have no more genetic diversity than much smaller groups. The latest revelation may explain how large populations feature relatively limited genetic variation, though researchers say such an explanation is theoretical.

To solve the mystery, more research must be done.

"We will only be able to understand this fully if we can compare results from across different species," Simon Martin, a research fellow at the University of Cambridge, said in a news release. "Extending our knowledge to butterflies is a step towards explaining these much broader patterns in nature; it's only by doing this kind of research that we will know whether these ideas are right or not."

The benefits of genetic conformity isn't yet clear, and researchers believe the newly discovered mechanism could render species less able to adapt in the future by deleting variations that might have come in handy later on.

"Variation is a kind of raw material and you don't necessarily use it all at any one time," Martin explained. "It's something that could be used to adapt and change in the future."

"Mutations that have no effect on survival today may be a source of beneficial variation in the future," he added.

The new research was published this week in the journal Genetics.