Population genetics of the naked mole-rat Heterocephalus glaber: The role of rivers in shaping genetic structure

Abstract

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We used nested clade phylogeographic analysis (NCPA) of mitochondrial DNA sequence data to examine the processes contributing to population structure in naked mole-rats. We examined sequence variation in the (1097 bp) control region D-loop of the mitochondrial genome in 303 individuals from 174 colonies of naked mole-rats (Heterocephalus glaber) located mainly within an 870 km2 area in Meru National Park, Kenya. Four rivers were found to be correlated to a significant fragmentation inference in the NCPA. The largest pairwise divergence between haplotypes from populations separated by rivers was 2.74%, which was well over half of the divergence reported between the extremes of the distribution from southern Ethiopia to southern Kenya (4.6%). However, the size of the river (measured in current discharge) was not a good predictor of the amount of sequence divergence between populations separated by a river. It appears that a large-scale historical fragmentation event may have conflated fragmentation patterns on a smaller scale, when recent colonization and range expansion brought two old lineages together at a location with a relatively small river separating them.

Keywords

• phylogeography
• nested clade analysis
• isolation-by-distance
• fragmentation
• genetic structure
• river