Patterns of genetic diversity in vervet monkeys (Chlorocebus aethiops) from the south eastern regions of South Africa

[摘要] English: Vervet monkeys (Chlorocebus aethiops) are one of the most widely distributedprimate species in Africa. The aim of this study was to determine the level of geneticdifferentiation among conspecific vervet monkey populations in the south-easternregions of South Africa, as part of a bigger project to determine levels ofdifferentiation across South Africa. For this purpose, samples were taken from fourlocalities in the Free State Province (Soetdoring Nature Reserve (NR), Gariep DamNR, Sandveld NR and the Parys area), four Eastern Cape locations (Tsolwana NR,Baviaanskloof NR, Shamwari Private Game Reserve (PGR) and the Nelson MandelaMetropolitan University (NMMU) campus, Port Elizabeth), three Kwa-Zulu Natallocation (St. Lucia area) and one Limpopo Province locality. Genetic differentiationwas quantified using sequence data from a portion of the mtDNA control region.Twelve Haplotypes were identified within the total sample group. The nucleotidediversity for each grouping was calculated over all loci. Nucleotide diversity rangedfrom 0 to 0.038% ±0.02. Haplotype frequencies distribution among samples wascalculated. An analysis of Molecular Variance (AMOVA) test was conducted andpopulation pairwise FST values were estimated. The AMOVA test revealed that themajority of the genetic diversity occurred among the different groups (52.5%), withonly 4.9% of the variation found within populations. The populations were assignedto groups according to geographic origins. The pairwise analysis identifiedsignificant levels of genetic variation among populations, with an average FST valueof 0.851. These haplotypes were found to coincide with the geographical borders ofProvinces. A ML tree was constructed using the haplotype data, and results showedclustering corresponding to geographical borders. A phylogenetic network wasconstructed, and this showed clustering similar to that found with the ML treeanalysis. According to these results it is clear that there is genetic structuring amongvervet monkey populations in South Africa. This clustering of populations can bepotentially explained by female philopatry and geographical barriers. Femalephilopatry is a well known occurrence amongst Cercopithecine primates. Theoccurrence of geographical barriers, such as rivers and mountains had influence onmigration rates and genetic structuring. This clustering pattern observed withmtDNA analysis contradicts results from previous studies working with nuclear DNAmarkers. This can be caused by various factors. Except for female philopatryhaving an effect on mtDNA differentiation patterns, it should be noted that the fasterevolutionary rate of mtDNA vs. nuclear DNA can also cause different geneticpatterns. The effective population size of mtDNA is also four-fold smaller than that ofnuclear genes, and will also cause skewed results when comparing mtDNA data withnuclear DNA data. No reliable recommendations can be made toward the release ofrehabilitated vervet monkeys, as further analysis is needed. It is thus suggested touse both genetic markers in follow-up studies. An increase in sample size from abroader geographical range is also recommended. In addition to further work onpatterns of genetic variation, the adaptive significance of observed geneticdifferences should also be investigated.

[发布机构] University of the Free State