Genetic variation in behavior occurs between species and within species. Describe the genetic basis for the difference in mating behaviors in closely related species of voles

Question

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Answer 1

Most voles, are promiscuous; they have multiple mates. However, some voles form lifelong, largely monogamous relationships. For example, in prairie voles, a permanent social bond forms after a night of repeated matings.

One genetic basis for this behavior is the control over the number and distribution of oxytocin receptors in the brain. Monogamous prairie voles have many oxytocin receptors in the part of the brain associated with social learning. Promiscuous mountain voles have far fewer of these receptors. The hormone oxytocin plays a central role in a female prairie vole's bonding behavior. When females who are part of an established pair are injected with a chemical that interferes with oxytocin action, they dump their long term partners in favor of other males.

Another genetic role is found in males. Variations in the distribution of receptors for another hormone (arginine vasopressin, or AVP) correlate with bonding tendency. Compared to males of promiscuous vole species, males of monogamous species have more AVP receptors. Scientists isolated the prairie vole gene for the AVP receptor and used genetic engineering to insert it into the brain of male mice, which are naturally promiscuous. After this treatment, the genetically modified mice preferred a female with whom they had already mated over an unfamiliar female. These results confirm the role of AVP in fostering monogamy among male rodents.