Micro‐ and macrogeographical genetic structure of colonies of naked mole‐rats Heterocephalus glaber

Abstract

Patterns of genetic structure in eusocial naked mole-rat populations were quantified within and among geographically distant populations using multilocus DNA fingerprinting and mitochondrial DNA (mtDNA) sequence analysis. Individuals within colonies were genetically almost monomorphic, sharing the same mtDNA control region haplotype and having coefficients of band sharing estimated from DNA fingerprints ranging from 0.93 to 0.99. Family analysis of a hybrid captive colony of naked mole-rats with increased levels of genetic variability using multilocus DNA fingerprinting gave results consistent with Mendelian inheritance, and has revealed for the first time that multiple paternity can occur. In a survey of wild colonies from Ethiopia, Somalia and locations in northern and southern Kenya, we have examined mtDNA control region sequence variation in 42 individuals from 15 colonies, and together with multilocus DNA fingerprinting and mtDNA cytochrome-b sequence analysis in selected individuals have shown that these populations show considerable genetic divergence. Most of the variance in sequence divergence was found to be between geographical locations (phi ct = 0.68) and there was a significant correlation between sequence divergence and geographical separation of haplotypes. Six colonies from Mtito Andei in southern Kenya shared the same control region haplotype, suggesting a recent common maternal ancestor. In contrast, out of four colonies at Lerata in north Kenya, three haplotypes were identified, and phylogenetic analysis suggests that this area may be a zone where two distinct lineages are in close proximity. Genetic distances were maximal between Ethiopian and southern Kenyan populations at 5.8% for cytochrome-b, and are approaching interspecific values seen between other Bathyergids.

Sperm structure and motility in the eusocial naked mole-rat, Heterocephalus glaber: a case of degenerative orthogenesis in the absence of sperm competition?

“…The high inbreeding coefficient reported in a previous study (F = 0.45) among four wild-caught colonies of naked mole-rats in Kenya [28], can be due to the fact that three of these colonies were collected within 5 km of each other. New colonies of naked mole-rats are usually formed by fissioning and thus neighbouring colonies could have a recent common maternal ancestor [23,29]. …”

“…Although not strictly monogamous, as multi-paternity has been recorded for this species [23], most other males and all other females (subordinates) are reproductively suppressed. This restriction of breeding to a small subset of the entire population (queen and 1-3 breeding males) possibly presents a low risk for sperm competition and it is predicted to have shaped the structure (simple) and motility (slow) of spermatozoa in this species.…”

Kin in space: social viscosity in a spatially and genetically substructured network

“…Owing to philopatry and strategies of delayed dispersal (social viscosity), individuals are often physically assorted into kin clusters where animals share the same alleles by descent with an increased probability (Dobson 1982;Fowler 2005). For communally breeding species, where the average relatedness within these clusters is high and close relatives recognize each other, genetic structure is often dictated by the placement of related individuals and usually co-varies with social structure ( Faulkes et al 1997;Dobson 1998). For such systems, kin selection theory provides an appealing solution to understand how even costly social behaviours such as cooperation and altruism evolve as a direct evolutionary consequence of inclusive fitness benefits (Hamilton 1964;Griffin & West 2003).…”

Effects of habitat fragmentation on population genetic structure in the white-footed mouse (Peromyscus leucopus)

“…Even though published measures of fragmentation at local scales are becoming more sophisticated (see van Apeldoorn et al 1992;Celada et al 1994;Fitzgibbon 1997), few authors have investigated possible correlations between these measures and within-population levels of variation (e.g., Faulkes et al 1997).…”