Biology subjects

Grobler, J. P.

Publications and source records attributed to Grobler, J. P..

3 recordsLinked to original sources

bioRxiv2022

Evidence of selection in UCP1 gene region suggests local adaptation to irradiance rather than cold temperatures in savanna monkeys (Chlorocebus spp.)

The genus Chlorocebus is widely distributed throughout sub-Saharan Africa, and in the last 300 thousand years expanded from equatorial Africa into the southernmost latitudes of the continent. In these new environments, colder climate was a likely driver of natural selection. We investigated population-level genetic variation in the mitochondrial uncoupling protein 1 (UCP1) gene region - implicated in non-shivering thermogenesis within brown/beige adipocytes - in 73 wild savanna monkeys from three taxa representing this southern expansion (C. pygerythrus hilgerti, C. cynosuros, C. p. pygerythrus) ranging from Kenya to South Africa. We found 17 SNPs with extended haplotype homozygosity consistent with positive selective sweeps, 10 of which show no significant LD with each other. Phylogenetic generalized least squares modeling with ecological covariates suggest that most derived allele frequencies are significantly associated with solar irradiance and winter precipitation, rather than overall low temperatures. This selection and association with irradiance appears to be driven by a population isolate in the southern coastal belt of South Africa. We suggest that sunbathing behaviors common to savanna monkeys, in combination with strength of solar irradiance, may mediate adaptations to thermal stress via non-shivering thermogenesis among savanna monkeys. The variants we discovered all lie in non-coding regions, some with previously documented regulatory functions, calling for further validation and research.

genetics↗

bioRxiv2020

Anthropogenic food enhancement alters the timing of maturational landmarks among wild savanna monkeys (Chlorocebus pygerythrus)

ABSTRACTAnthropogenic landscapes are rapidly replacing natural nonhuman primate habitats. Yet, the access to anthropogenic resources on primate biology, health, and fitness remain poorly studied. Given their ubiquity across a range of human impacted landscapes, from cities to national parks, savanna monkeys (Chlorocebus spp.) provide an excellent study system in which to test these effects. We compared body condition and reproductive maturation in vervets (Chlorocebus pygerythrus) inhabiting a private farm in !Gariep Dam, with ample access to anthropogenic foods, and wild-foraging vervets in Soetdoring Nature Reserve, South Africa. Overall, vervets in !Gariep show significantly thicker skin folds, and higher BMI and body mass, than those in Soetdoring, suggesting increased fat deposition. Males in !Gariep have larger relative testis volumes at peri-pubescent ages compared to those in Soetdoring, suggesting early reproductive maturation associated with age-specific increases in body mass. Females from !Gariep showed evidence of an earlier onset of reproduction than those in Soetdoring, based on parity status as assessed by nipple length and evidence of lactation. Parity status at sub-adult dental ages was also strongly associated with body mass. These results are consistent with a positive effect of anthropogenic food-enhancement on body fat deposition, potentially linked to an earlier onset of reproductive maturation. Further investigation into primate responses to cultivated resources will inform our understanding of the broader effects of food enhancement on developmental plasticity.Competing Interest StatementThe authors have declared no competing interest.View Full Text

zoology↗

bioRxiv2019

Assessing introgressive hybridization in roan antelope (Hippotragus equinus): Lessons from South Africa

Biological diversity is being lost at unprecedented rates, with admixture and introgression presenting major threats to species conservation. To this end, our ability to accurately identify introgression is critical to manage species, obtain insights into evolutionary processes, and ultimately contribute to the Aichi Targets developed under the Convention on Biological Diversity. A case in hand concerns roan antelope, one of Africas most iconic large mammal species. Despite their large size, these antelope are sensitive to habitat disturbance and interspecific competition, leading to the species being listed as Least Concern but with decreasing population trends, and as extinct over parts of its range. Molecular research identified the presence of two evolutionary significant units across their sub-Saharan range, corresponding to a West African lineage and a second larger group which includes animals from East, Central and Southern Africa. Within South Africa, one of the remaining bastions with increasing population sizes, there are a number of West African roan antelope populations on private farms, and concerns are that these animals hybridize with roan that naturally occur in the southern African region. We used a suite of 27 microsatellite markers to conduct admixture analysis. Our results unequivocally indicate evidence of hybridization, with our developed tests able to accurately identify F1, F2 and non-admixed individuals at threshold values of qi = 0.20 and qi = 0.15, although further backcrosses were not always detectable. Our study is the first to confirm ongoing hybridization in this iconic African antelope, and we provide recommendations for the future conservation and management of this species.

zoology↗