Population genetic structuring in the common mole-rat, Cryptomys hottentotus hottentotus

Doctoral Thesis


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University of Cape Town

This thesis addresses the population genetic consequences of divergent social structure and dispersal regimes in two study populations of the common mole-rat Cryptomys hottentotus hottentotus. Aspects relating to the relationship between, gene flow and genetic variation, the roles of mutation and drift in promoting genetic structuring, and the role of genetic parentage in the species' mating system were investigated using a suite of cryptomys-specific microsatellite markers. C. h. hottentotus is a social species living in colonies of 2-14 individuals, permanently inhabiting a network of burrows. The species is a co-operative whose colonies are composed of a breeding pair, their offspring and a number of potentially unrelated individuals. C. h. hottentotus is an obligate outbreeder whose offspring delay dispersal and the opportunities for independent reproduction until both social and ecological conditions are favourable. The species is widely distributed across South Africa from extreme arid regions where low rainfall restricts dispersal for much of the year, to highly mesic areas where dispersal is facilitated all year round. In response to varying ecological constraints on dispersal, the species displays differential degrees of social elaboration across its range. This appears to be in response to the high energetic costs of burrowing and the low probability of locating geophyte clumps in increasingly arid environments.

Bibliography: leaves 118-135.