Abstract
BackgroundThe mechanisms that underlie the diversification of tropical animals remain poorly understood, but new approaches that combine geo-spatial modeling with spatially explicit genetic data are providing fresh insights on this topic. Data about the diversification of tropical mammals remain particularly sparse, and vanishingly few opportunities exist to study endangered large mammals that increasingly exist only in isolated pockets. The chimpanzees of Cameroon represent a unique opportunity to examine the mechanisms that promote genetic differentiation in tropical mammals because the region is home to two chimpanzee subspecies: Pan troglodytes ellioti and P. t. trogolodytes. Their ranges converge in central Cameroon, which is a geographically, climatically and environmentally complex region that presents an unparalleled opportunity to examine the roles of rivers and/or environmental variation in influencing the evolution of chimpanzee populations.ResultsWe analyzed microsatellite genotypes and mtDNA HVRI sequencing data from wild chimpanzees sampled at a fine geographic scale across Cameroon and eastern Nigeria using a spatially explicit approach based upon Generalized Dissimilarity Modeling. Both the Sanaga River and environmental variation were found to contribute to driving separation of the subspecies. The importance of environmental variation differed among subspecies. Gene-environment associations were weak in P. t. troglodytes, whereas environmental variation was found to play a much larger role in shaping patterns of genetic differentiation in P. t. ellioti.ConclusionsWe found that both the Sanaga River and environmental variation likely play a role in shaping patterns of chimpanzee genetic diversity. Future studies using single nucleotide polymorphism (SNP) data are necessary to further understand how rivers and environmental variation contribute to shaping patterns of genetic variation in chimpanzees.Electronic supplementary materialThe online version of this article (doi:10.1186/s12862-014-0274-0) contains supplementary material, which is available to authorized users.
Highlights
The mechanisms that underlie the diversification of tropical animals remain poorly understood, but new approaches that combine geo-spatial modeling with spatially explicit genetic data are providing fresh insights on this topic
The genetic data consisted of autosomal microsatellite genotype profiles of 187 unrelated individuals sampled from 28 locations across eastern Nigeria and Cameroon and 604 mtDNA sequences sampled from 35 locations across the study region (Figure 2)
This method fits genetic distance matrices from both microsatellite (FST) and mtDNA data against straight-line geographic distance, topographic, climatic and vegetation variables assumed to contribute to chimpanzee habitat ecology and biogeographic boundaries
Summary
The mechanisms that underlie the diversification of tropical animals remain poorly understood, but new approaches that combine geo-spatial modeling with spatially explicit genetic data are providing fresh insights on this topic. Tropical Africa is noted for exhibiting a complex forest history that has undergone considerable change along with the Earth’s climate, and the behavioral ecology of African primates often reflects a shared history with their habitats [5,6,7] This relationship has been proposed to have influenced the diversification of rainforest taxa due to the fact that previously continuous populations were isolated from one another in forest “refuges” that persisted during periods of maximum glaciation. The Gap has been proposed to have been a barrier to dispersal for several species which resulted in the formation of new species This process of separation and speciation across the Gap has been proposed to account for the unique faunal assemblages of the Upper and Gulf of Guinea forest blocks, which are both two of the world’s original Global Biodiversity Hotspots [2,4,11,12]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
