Breeding tactics, social structure and genetic variation in mammals: problems and prospects

Breeding tactics and social structure are among the primary determinants of the level and distribution of genetic variation in a population, giving rise to genetic structure. However the effects of such behaviors are neither intuitively obvious nor predictive. Interpretations of genetic interactions are hampered by a lack of suitable underlying models and the resulting weak empirical data base means that we are presently unable to answer fundamental questions such as whether the social structure exhibited by a species has any necessary or consistent relationship with the extent of genetic population structure in the species. In this review I present a brief overview of recent theoretical models, and summarise results of the two most common empirical approaches; namely, genetic comparison of identified social groups, and studies of arbitrarily selected samples. Some recommendations are made with respect to future empirical investigations. Increased sophistication in classifying social complexity will be necessary to elucidate the effects of social structure and breeding tactics on partitioning of genetic variation, and to determine the true correlation between social level and genetic structure.