Female Mice Mating with Several Partners Produce Sexier Sons

Promiscuity is quite rampant in nature because it helps gene diversity. A new study by Utah biologists found that promiscuous mice moms bore sexier offsprings. These Casanova mice get hooked more often than others because they produce urinary pheromones. However, they often die young.

"If your sons are particularly sexy, and mate more than they would otherwise, it's helping get your genes more efficiently into the next generation," says biology professor Wayne Potts, senior author of the new study.

It's only now that researchers are finding a link between parents' lifestyle and its effects on their babies.

"This study is one of the first to show this kind of 'epigenetic' process working in a way that increases the mating success of sons," Potts said in a news release.

Getting mice to fall in Love                                                       

Usually, researchers conducting lab tests breed mice in a secluded environment by letting one male mate with one female. However, in nature, mice have to compete for their lovers.

So, Potts and colleagues bred the mice in the study in a semi-natural enclosure, where they could move freely about the cages and choose their mates. Scientists bred another set of mice according to lab standards.

Mice growing up in semi-natural cages were considered promiscuous and those in the closed cages were labelled monogamous.

For the experiment, researchers bred different types of mice; promiscuous mom and dad, monogamous mom and dad, promiscuous mom with monogamous dad, and monogamous mom with promiscuous father.

Researchers found that sons of promiscuous parents had 31 percent more major urinary proteins or MUPs than other babies.

The study is published in the journal Proceedings of the National Academy of Sciences.

Another study by Potts and Adam C. Nelson found that just 48 percent of the sexy mice lived till the end of the experiment whereas 80 percent of normal-mice lived till a grand-old age. Producing the 'cologne' that attracts females requires more energy, which is probably why the jocks among mice tend to die early. Nelson is co-author of the study.

Previous research on sheep, too, has shown that the sexy male gets more females, but has a shorter lifespan.