Simulating the effects of kinship and postmarital residence patterns on mitochondrial DNA diversity in mortuary contexts.

Abstract

We explore the observable outcome in mtDNA diversity of different kinship systems and associated postmarital residence patterns in the archeological record, using simulations at the intrapopulation level. Four kinship systems were simulated from a set of variable fertility and mortality scenarios. Initial conditions consisted of six clusters of variable size and a random number of assigned haplotypes, with individuals migrating between groups and reproducing for 15 generations. Each 15-generation span was simulated 500 times to obtain representative intrasite mtDNA diversity distributions for each kinship system. Additional simulations were devised to consider the effect of migration and different rates of adherence to kinship norms. Matrilineal kinship generates low male and female haplotype diversities that are statistically indistinguishable from each other, while female diversity in bilateral kinship with matrilocality is significantly lower than that observed in male diversity. Furthermore, mtDNA diversity generated by patrilineal kinship is very high. The effect of noncompliance with kinship rules is low; migration has a considerable impact on diversity, eventually obscuring the effect of kinship practices. The results of the simulations can be applied to ancient mtDNA data from archeological contexts, as exemplified with data from two studies. On a broader scale, the kinship system followed by the sampled population, can lead to either over- or underestimation of mtDNA population diversity. The results of the simulations can be used in the design of inferential frameworks to discern kinship scenarios in the archeological record, based on mtDNA and other types of evidence.