ena-STUDY-Hendrik-14-11-2017-09:01:16:587-149
Spatial genetic diversity in the Cape mole-rat, Georychus capensis: Extreme isolation of populations in a subterranean species
The subterranean niche harbours animals with extreme adaptations to traverse it. These adaptations decrease the vagility of taxa and, along with other behavioural adaptations, often result in isolated populations characterized by small effective population sizes, high inbreeding, population bottlenecks, genetic drift and consequently, high spatial genetic structure. Although information is available for some species, estimates of genetic diversity and whether this variation is spatially structured, is lacking for the Cape mole-rat (Georychus capensis). By adopting a range-wide sampling regime and employing two variable mitochondrial markers (cytochrome b and control region), we report on the effects that life-history, population demography and geographic barriers had in shaping genetic variation and population genetic patterns in G. capensis. We also compare our results to information available for the sister taxon of the study species, Bathyergus suillus. Georychus capensis exhibits low genetic diversity relative to the concomitantly distributed B. suillus, most likely due to life-history differences in habitat specificity and historical population declines. In addition, the isolated nature of G. capensis populations and low levels of population connectivity has led to genetic differentiation, possibly aided by genetic drift. Not surprisingly therefore, G. capensis exhibits pronounced spatial structure. Along with geographic distance and demography, other factors shaping the genetic structure of G. capensis include the historical and contemporary impacts of mountains, rivers, sea-level fluctuations and elevation. Given the isolation and differentiation among G. capensis populations, the monotypic genus Georychus may represent a species complex.
The subterranean niche harbours animals with extreme adaptations to traverse it. These adaptations decrease the vagility of taxa and, along with other behavioural adaptations, often result in isolated populations characterized by small effective population sizes, high inbreeding, population bottlenecks, genetic drift and consequently, high spatial genetic structure. Although information is available for some species, estimates of genetic diversity and whether this variation is spatially structured, is lacking for the Cape mole-rat (Georychus capensis). By adopting a range-wide sampling regime and employing two variable mitochondrial markers (cytochrome b and control region), we report on the effects that life-history, population demography and geographic barriers had in shaping genetic variation and population genetic patterns in G. capensis. We also compare our results to information available for the sister taxon of the study species, Bathyergus suillus. Georychus capensis exhibits low genetic diversity relative to the concomitantly distributed B. suillus, most likely due to life-history differences in habitat specificity and historical population declines. In addition, the isolated nature of G. capensis populations and low levels of population connectivity has led to genetic differentiation, possibly aided by genetic drift. Not surprisingly therefore, G. capensis exhibits pronounced spatial structure. Along with geographic distance and demography, other factors shaping the genetic structure of G. capensis include the historical and contemporary impacts of mountains, rivers, sea-level fluctuations and elevation. Given the isolation and differentiation among G. capensis populations, the monotypic genus Georychus may represent a species complex.