Search

Grasscutter (Thryonomys swinderianus) is a large-body old world rodent found in sub-Saharan Africa. The body size and the unique taste of the meat of this major crop pest have made it a target of intense hunting and a potential consideration as a micro-livestock. However, there is insufficient knowledge on the genetic diversity of its populations across African Guinean forests. Herein, we investigated the genetic diversity, population structures and evolutionary history of seven Nigerian wild grasscutter populations together with individuals from Cameroon, Republic of Benin, and Ghana, using five mitochondrial fragments, including D-loop and cytochrome b (CYTB). D-loop haplotype diversity ranged from 0.571 (± 0.149) in Republic of Benin to 0.921 (± 0.013) in Ghana. Within Nigeria, the haplotype diversity ranged from 0.659 (± 0.059) in Cross River to 0.837 (± 0.075) in Ondo subpopulation. The fixation index (FST), haplotype frequency distribution and analysis of molecular variance revealed varying levels of population structures across populations. No significant signature of population contraction was detected in the grasscutter populations. Evolutionary analyses of CYTB suggests that South African population might have diverged from other populations about 6.1 (2.6–10.18, 95% CI) MYA. Taken together, this study reveals the population status and evolutionary history of grasscutter populations in the region.

Cichlids are among the economically important which serve as a source of food for people ‎around the world. A deep understanding of the population structure and genetic diversity of ‎cichlids are vital for initiation of conservation policies and sustainable aquaculture. There is ‎paucity of information on the patterns of genetic variations among and within cichlids in ‎North-central Nigeria. This study, therefore, investigated population genetic structure of ‎Coptodon zillii, Oreochromis niloticus, and Hemichromis fasciatus collected from different ‎freshwater bodies in North-central Nigeria. Genomic DNA was extracted, and five highly ‎polymorphic RAPD primers were used for RAPD-PCR amplification and genotyping of the ‎fish. Genetic polymorphism within and between the three tilapia species were examined. ‎Percentages of polymorphism loci, pairwise population matrix, analysis of molecular variance ‎‎(AMOVA), and genetic distances of cichlid populations were determined using standard ‎methods, and dendrograms were constructed using an un-weighted pair group method of ‎arithmetic mean (UPGMA). Overall, percentages of estimated molecular variance within and ‎among C. zillii, H. fasciatus and O. niloticus populations were 5% and 95%; 4% and 96% and ‎‎13% and 87%, respectively. Our results suggest that the three cichlids have close evolutionary ‎relationship and there were no distinct genetic differences on the basis on sampling locations. ‎C. zillii and H. fasciatus are more genetically closer than O. niloticus. This study concludes that ‎RAPD is useful in studying the population genetic structure of cichlids. This study therefore ‎recommends conservation of genetic pool of cichlid species through proper maintenance and ‎restoration of polluted habitat to guarantee sustainable fishery production. However, markers ‎such as microsatellite DNA can be assayed in further studies for better results‎.