Coupled biochemical genetic and karyomorphological analyses for taxonomic classification - A case study of Schizothorax species complex (Teleostei: Cyprinidae)

Abstract

Biochemical genetic and karyomorphological studies were evaluated for taxonomic importance. Five Schizothorax species namely: Schizothorax niger, Schizothorax curvifrons, Schizothorax esocinus, Schizothorax labiatus and Schizothorax plagiostomus were studied in this experiment as a model for serum proteins and chromosomal analysis. Serum protein band patterns of Schizothorax species complex were studied by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Their electrophoretograms revealed similarities as well as differences in the number and molecular weight of protein bands. S. esocinus showed five bands, S. curvifrons five, S. niger seven, S. labiatus and S. plagiostomus each showed six bands; they also showed species characteristic bands. Karyotypic study of these was carried out. The diploid chromosome numbers recorded were 98 in S. niger (24 m + 32 sm + 22 st + 20 t), 98 in S. esocinus (30 m + 22 sm + 10 st + 36 t), 98 in S. labiatus (24 m + 20 sm + 2 st + 52 t), 96 in S. plagiostomus (24 m + 18 sm + 5 4t) and 94 in S. curvifrons (26 m + 20 sm + 20 st + 28 t). Coupled biochemical genetic and karyomorphological analysis proved a good taxonomic tool as the results were decisive in establishing the species status of these species despite their overlapping morphological characters.

Keywords: Schizothorax, serum proteins, karyotype, taxonomy, biochemical

African Journal of Biotechnology, Vol 13(14), 1623-1630