Evolutionary benefits of sex in difficult places

Jun 14, 2012

(Phys.org) -- University of Auckland scientists have provided the first experimental explanation of how sexual reproduction helps species adapt in challenging real-world environments, solving a classic conundrum in evolutionary biology.

“According to classic evolutionary , should actually retard species’ ability to adapt to complex environments and in the long run prevent the evolution of new species,” explains lead researcher Dr Mat Goddard. “But in the real world, sex is a highly successful strategy that doesn’t prevent new species from evolving, so what we see in nature doesn’t tally with the theory. Our experimental work provides the first explanation for this and supports an alternate evolutionary theory.”

As organisms adapt to environmental challenges they accumulate genetic changes that help them survive. Since sexual reproduction produces offspring with a mix of genes from both parents, in theory, sex between organisms adapting to different environments should be detrimental. It would produce offspring poorly adapted to either environment because helpful genes are diluted and, according to classic theory, genes that are beneficial in one situation are detrimental in another.

To test the theory the researchers developed special yeast that could be switched from asexual to sexual forms. Two groups of yeast grown in different environments were allowed to sexually reproduce, to see whether this slowed the species’ simultaneous adaptation to both environments as predicted by the theory.

In fact, sexual reproduction proved advantageous, allowing more rapid adaptation to both environments even when there was interbreeding between the two groups. The results were consistent with a little-known alternate theory, which states that genes that confer a benefit in one environment are not necessarily detrimental in another and would therefore not disadvantage the offspring of mixed parents.

“If the classic theory were true, then any breeding between groups of organisms adapting to different environments would dramatically slow their evolution. So to explain how new species evolve, classical theorists have had to come up with all sorts of convoluted scenarios, like the emergence of ‘magic genes’ for mate choice to prevent sexual reproduction between populations,” says Dr Goddard.

“Our work is much more consistent with what we see in the real world. It supports an alternate theory, in which organisms adapting to different environmental niches can live alongside one another and interbreed occasionally but this doesn’t compromise their evolution or the eventual development of new , in fact sex enhances this process.”

The research was funded by a Marsden grant and a University of Auckland PhD scholarship to Jeremy Gray, and has been published online today in the journal Ecology Letters.

Explore further: A clear, molecular view of how human color vision evolved

Related Stories

Sex: it's a good thing, evolutionarily speaking

May 30, 2012

(Phys.org) -- Sure, sex may be fun, but it’s a lot of work, and the payoff is by no means certain. Scientists have speculated for a long time on why all living things don’t simply make like amoebas ...

Researcher argues that sex reduces genetic variation

Jul 07, 2011

Biology textbooks maintain that the main function of sex is to promote genetic diversity. But Henry Heng, Ph.D., associate professor in WSU's Center for Molecular Medicine and Genetics, says that's not the case.

Evolution revolution

Mar 26, 2012

Developments in evolutionary biology have a significant impact on the way we look at the world and ourselves in it, according to a conservation scientist who will be speaking on the subject at Cambridge University’s ...

Recommended for you

Contrasting views of kin selection assessed

Dec 17, 2014

In an article to be published in the January issue of BioScience, two philosophers tackle one of the most divisive arguments in modern biology: the value of the theory of "kin selection."

Microbiome may have shaped early human populations

Dec 16, 2014

We humans have an exceptional age structure compared to other animals: Our children remain dependent on their parents for an unusually long period and our elderly live an extremely long time after they have ...

DNA sheds light on why largest lemurs disappeared

Dec 16, 2014

Ancient DNA extracted from the bones and teeth of giant lemurs that lived thousands of years ago in Madagascar may help explain why the giant lemurs went extinct. It also explains what factors make some surviving ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

trekgeek1
5 / 5 (1) Jun 14, 2012
Evolutionary benefits of sex in difficult places

Like in airplane bathrooms?

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.