Genetic Characterization of the Genus ‘Barbus’ (Cyprinidae) in the Lake Victoria Drainage System, Kenya

Abstract

The genus ‘Barbus’ belongs to a speciose taxonomically complex and heterogeneous assemblage of cyprinid fish. In Lake Victoria drainage basin in Kenya, ten endemic species of ‘Barbus’ are reported, which play a significant role in food security and socio-economic development of the local community. Although these species are identified using morphological characters, confusion may occur when trying to distinguish morphologically similar species. Recent molecular work in the region has suggested presence of introgression within certain ‘Barbus’ species further complicating the taxonomy and species identification in the group. In this study, we obtained cytochrome b and GH-intron 2 gene sequences of nine ‘Barbus’ species sampled in the Lake Victoria drainage basin in Kenya. We conducted Maximum likelihood and Bayesian phylogenetic analyses to establish their evolutionary relationships in relation to other ‘Barbus’. The results showed distinct lineages of ‘Barbus’ species not subjected to introgression/hybridization. Herein, we present new sequences of cytochrome b and GH DNA for small African ‘Barbus’. We also report new sequences of cytochrome b for Labeobarbus altianalis sampled from the study site. The analyses further established ‘B.’ profundus to be a sister to ‘B.’ anema and not ‘B’. radiatus as originally described, a finding that compliments previous morphometric and meristic data suggesting ‘B.’ profundus to be a distinct species and not a subspecies of ‘B’. radiatus. These results demonstrate that molecular markers can provide additional support to inferences derived from morphological evidences. We hope that the newly established sequences from this study will enrich the online reference database and allow future molecular species identification of the African Barbs. In addition, this study contributes to a better understanding of phylogenetic relationships and diversity of ‘Barbus’ in the Lake Victoria Basin and Africa in general.