Fitness consequences of cousin marriage: a life-history assessment in two populations

Abstract Cousin marriage, a spousal union between close kin, occurs at high frequencies in many parts of the world. The rates cousin marriage humans are concordant with empirical studies that challenge traditionally held view reproduction kin is generally avoided animals. Similarly, some theoretical models animal behaviour show inbreeding avoidance more constrained than previously thought. Such highlight importance quantifying costs and benefits among over whole life-course. Here, we use genealogical data from two human populations (the Dogon Mali, Ancien Régime nobility Europe) to estimate these potential benefits. We compare age-specific fertility survival curves, as well projected growth rates, subpopulations each type. Fitness present terms reduced child (in both populations), while exist increased for men Dogon) women nobility). also find differences lineages function Finally, discuss trade-offs might shape decisions different ecological conditions.