Yeast Study Confirms the Advantages of Sex

It’s official: Sex is good for you. Well, at least it’s good for yeast.

From an evolutionary standpoint, sexual reproduction seems to have many disadvantages over the asexual variety.

It wastes time and energy, it mixes up perfectly good genes, and females, who do nearly all of the reproductive work, get to pass on only half their genetic material. So scientists have wondered: Why sex? August Weismann, a 19th century theorist, proposed that sexual reproduction helps speed up natural selection by allowing good genes to spread more quickly through a population and bad genes to disappear faster. That makes sex good for the species.

Although generally accepted, Weismann’s theory has been difficult to prove in the lab. But a team of British scientists has at last shown what is so beneficial about sex. In yeast, at least.

Yeasts include tiny organisms that reproduce both ways, sexually and asexually.

So Matthew Goddard and a team of scientists from Imperial College London made two versions of otherwise identical yeast, one that could reproduce both ways and one that could only reproduce asexually.

They found that under normal conditions, the two sorts fared equally well. But under extreme conditions, the sexually-reproductive yeast did better.

“Our results indicate that sexual reproduction can provide a selective advantage during adaptation to new environments,” they wrote in the current Nature.

“A challenge now is to understand the nature of the mutations that underlie adaptation and to extend these techniques to larger plants and animals,” they wrote.