Genomic imprinting, sex-biased dispersal, and social behavior.

Some genes carry a record of the sex of the gene's carrier in the previous generation that influences the gene's expression in this generation. This additional information can result in intragenomic conflicts between an individual's maternally and paternally derived alleles over behaviors that affect relatives with whom the individual has different degrees of maternal and paternal relatedness. Asymmetries of relatedness can arise because of sex-biased dispersal. For example, if females remain in their natal group and males disperse, female members of a group will all be matrilineal relatives, but may have unrelated fathers. Sex-linked inheritance creates an evolutionary bias in favor of social groups that trace descent through the homogametic sex. This bias has a positive and negative aspect. The positive aspect is increased relatedness among siblings of the homogametic sex. The negative aspect is the lack of sex-linked relatedness between parents and offspring of the heterogametic sex.