Two species of mice live in the Santa Cruz Mountains in California that share habitat and genetic lineage, but have very different social lives. TheCalifornia mouse or Peromyscus californicus is monogamous, whilethe deer mouse ( Peromyscus maniculatus ) is sexually promiscuous. Studying their differences at the genetic level, American researchers have shown that promiscuity helps strengthen the immune system.
Monogamy is a rare trait among mammals, present in only 5% of species. But why is promiscuity so successful? Comparing these two closely related rodents, Matthew MacManes and his colleagues at the University of California at Berkeley have concluded that the differences in the lifestyle of these two species have a direct impact on the communities of bacteria that reside within. of the female reproductive system. What’s more, these differences affect the diversity in genes intended to provide rodents with immunity to infectious diseases. Specifically,sexually promiscuous deer mice had twice the bacterial diversity of monogamous mice, and this, generation after generation, has strengthened the genome of the former. “The species, due to its sexual habits, is in contact with a greater number of individuals and exposed to a greater variety of bacteria, so thathas developed a more robust immune system“, clarifies MacManes.
The results, published inPLoS One, confirm thatdifferences in social behavior induce evolutionary changes at the genetic level. In fact, the researcher also investigates how DNA is modified based on other aspects of social behavior, for example the solitary life that some animals lead versus the coexistence in large groups for which other species choose. “In the coming years we are going to see an explosion in studies that answer one question: How can genes control what we do and how we behave?” Suggests MacManes.
