Genetic diversity and population structure of the endangered ripon barbel,Barbus altianalis(Boulenger, 1900) in Lake Victoria catchment, Kenya based on mitochondrial DNA sequences

Abstract

Summary Approximately 850 bp of the mitochondrial control region was used to assess the genetic diversity, population structure and demographic expansion of the endangered cyprinid Barbus altianalis, a species known to be potamodramous in the Lake Victoria drainage system. The 196 samples taken from the four main rivers draining the Lake Victoria catchment (Nzoia, Yala, Nyando and Sondu–Miriu) yielded 49 mitochondrial DNA haplotypes; 83.7% thereof were private haplotypes restricted to particular rivers. The overall mean haplotype diversity was high (0.93663 ± 0.008) and ranged between 0.566 (Sondu – Miriu) and 0.944 (Nzoia). The overall mean nucleotide diversity was low (0.01322 ± 0.00141), ranging from 0.0342 (Sondu – Miriu) to 0.0267 (Nzoia). Population differentiation tests revealed strong and highly significant (P ≤ 0.001) segregation of populations in the four river basins. FST values among the four river‐based populations ranged from 0.05202 to 0.44352. The samples formed two main haplotype networks based on a 95% parsimony criterion, each exhibiting a strong signature of past population expansion. The smaller network was restricted to the River Nzoia, whereas the larger network contained representatives from all four rivers; within this the central haplotypes were found in more than one river, whereas the peripheral haplotypes tended to be river‐specific. The degree of population differentiation and the number of river‐specific haplotypes are too high to be explained by recent anthropogenic impacts alone and suggest that the species has probably existed in the Lake Victoria catchment as two populations: the now ‘extinct’ migratory population and the extant river restricted non‐migratory populations.

Peer Review #1 of "Evolution of African barbs from the Lake Victoria drainage system, Kenya (v0.1)"

“…8), representing five localities. The lack of Cytb diversity among our L. altianalis specimens sharply contrasts with a previous study of this species in this area that reports high haplotype diversity for the mitochondrial control region(Chemoiwa et al (2013). Although our phylogenetic analyses provide little resolution within Labeobarbus, they suggest that our L.…”

“…This species has historically constituted an important fishery in this region (Whitehead, 1959), but overfishing has severely decimated its populations (Ochumba and Many Ala, 1992). Genetic diversity for this species in the Kenyan LVD has been studied with the mitochondrial control region, which revealed some population structure (Chemoiwa et al, 2013). Muwanika et al (2012) Manuscript to be reviewed sequences from this species in the Kenyan LVD will allow examination of differences among the populations from both countries.…”

High genetic diversity and population differentiation in Clarias gariepinus of Yala Swamp: evidence from mitochondrial DNA sequences

“…Multi-modal and more ragged distributions are a signature for more stable populations (Rogers & Harpending, 1992), reported in a number of fish taxa including Labeobarbus spp. Rüppell 1835 (Muwanika et al, 2012), Barbus altianalis (Boulenger 1900) (Chemoiwa et al, 2013) and C. batrachus (Lee & Sulaiman, 2015). LKG, however, showed a uni-modal and less ragged distribution, while LNG had a multi-modal and more ragged distribution, suggesting a recent population expansion in LKG, while LNG was a stable population.…”

“…Naturally small and isolated, satellite lakes have long been recognized as functional refugia for indigenous fish species (Kaufman & Ochumba, ; Kaufman et al , ), whose survival in the main lake is severely threatened or may be extirpated altogether, due to anthropogenic effects. The loss of ichthyofaunal biodiversity in the Lake Victoria basin has called for an urgent need to identify and conserve the remaining populations, including the genetic diversity they contain, as well as their habitats (Kaufman et al , ; Ojwang et al , ; Chemoiwa et al , ). In their study, Barasa et al () reported no significant differentiation between Lakes Victoria and Kanyaboli populations of C. gariepinus , but six private haplotypes were inferred in the Lake Kanyaboli population.…”

Morphological Characterization and Relationship between Morphometric Parameters and Standard Length Barbus altianalis (Boulenger, 1904) Populations in Lake Victoria Drainage Basin, Kenya

“…The possibility of two populations of many riverine species in River Sondu-Miriu has been reported [18]. Studies on trophic ecology [19] and current molecular studies [20] suggest the existence of non-migratory Barbus altianalis populations within the Lake Victoria catchment. It is not clear whether such changes from potamodromous to stationary behavior has been accompanied by morphological changes among populations of the species.…”