Genetic variation and lack of hybridization in five cichlid fish species in the Malagarasi River basin, Tanzania
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Date
2025
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Elsevier
Abstract
Among the most widely cultured groups of freshwater fish species are tilapiine cichlids. This has contributed to
introduction of cichlid fish species in area where they were not native. Consequently, has contributed to negative
ecological effects on local species and their habitats through competition, habitat alteration and loss of unique
population genetic structures due to hybridization. This research study aimed to assess the genetic status of five
cichlid fish species red listed by the International Union for Conservation of Nature (IUCN) as least concerned
species. A mitochondrial Cytochrome Oxidase Subunit I (COI) gene fragment from 112 individuals collected from
three sampling sites were used to determine the present genetic diversity of the cichlid species inhabit the
Malagarasi River system which discharge water into Lake Tanganyika. The highest nucleotide diversity (0.02 ±
0.01) and haplotype diversity (0.94 ± 0.04) were recorded from Haplochromis pharyngalis. The lowest levels of
nucleotide and haplotype diversity were recorded from Oreochromis leucostictus. The Analysis of Molecular
Variance (AMOVA) resulted into statistically significant genetic differences (Φst: 0.96, P < 0.001) among the
cichlid species studied. The minimum spanning haplotype network and maximum-likelihood phylogenetic an
alyses support the AMOVA findings as no species is sharing any haplotype with other species. The values of
neutrality tests suggested that the studied cichlid fish species are stable and not expanding. These findings
highlight the necessity of conservation interventions in the area especially for the species which displayed low
nucleotide and haplotype diversity.
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Journal Article
Keywords
Fresh water, Genetic diversity, Hybridization, Phylogenetics, Tilapia species