mice in laboratoryA promiscuous mother may produce sons that are more appealing to female mice, according to a new study. Female mice are attracted to pheromones present in the urine of male mice. The male offspring of promiscuous mice produce more of this urinary pheromone, making them more alluring to females. There is one drawback to being sexier – the charming mice tended to have shorter life spans.

A research team led by senior author Prof. Wayne Potts from the University of Utah was responsible for the discovery. The study results, published in the journal Proceedings of the National Academy of Sciences, suggest the parents’ environment modifies the genes of the offspring. Previously, scientists had attributed many of these changes to alterations in DNA as it passes from one generation to the next.

To perform the study, the biologists raised ten generations of descendents of wild mice in cages with assigned mates. The scientists kept 23 male-female pairs of the domesticated mice in monogamous, non-social cages to ensure fidelity. They then assigned another 20 males and 40 females to a community cage where the mice could engage in social, promiscuous activities that required the males to compete for territory and mates.

The researchers found the male offspring of mice that had to compete produced 31 percent more of the major urinary proteins, or MUPs, that attract female mice than did the mice produced by chaste parents. Higher MUPs concentrations give the mice with the promiscuous mothers and competitive fathers a distinct advantage when it comes to mating, even though these sexier male offspring never had to compete.

Having a promiscuous father had the reverse effect. The researchers bred promiscuous and monogamous females with each type of males. They found that sons of promiscuous fathers had 5 percent less MUP than sons of monogamous fathers. The scientists concluded that this may be to prevent promiscuous fathers from competing with their sons.

The mice that produced more urinary proteins had shorter lives. Only 48 percent of the debonair mice lived to the conclusion of the experiment, as compared to 80 percent of the offspring of the monogamous parents. This is likely due to the increased energy required to make pheromones.

Source: Nelsona, Adam C., et al. "Reintroducing domesticated wild mice to sociality induces adaptive transgenerational effects on MUP expression." Proceedings of the National Academy of Sciences PNAS. 18 Oct 2013. Web. Retrieved 25 Nov 2013.

Keyword Tags: