Abstract:
Species of the Genus Puntius (Family Cyprinidae) are very important to Sri Lanka
as they represent the large portion (16 species) of freshwater fish fauna and their
high endemism. Most of the species are economically important as aquarium fish
and food fish. Economic importance as well as habitat degradation has resulted
most of the Puntius spp. to be threatened. Therefore conservation of these fishes
has become a priority at present. Correct identification, morphological and genetic
relationships of Puntius spp. are very important in this context. Accordingly the
present study was focused on investigations of the morphological and genetic
relationships among six selected Puntius spp.
Samples of six Puntius spp. namely P. litteya, P. nigrofascialus, P. dorsalis, P.
Jilamentosus, P. bimaculalus, and P. cho/a were collected form Nilwala river basin
and some of the meristic and morphometric data were recorded. These data were
subjected to hierarchical cluster analysis. Principle Component Analysis (PCA) and
Multi Dimensional Scaling (MDS), to determine their morphological relationships.
DNA was extracted from muscle tissue of each fish and subjected to two
molecular-based analysis; Polymerase Chain Reaction - Restriction Fragment
Length Polymorphism (PCR-RFLP) and Random Amplified Polymorphic DNA
(RAPD). In the PCR-RFLP analysis, a fragment of I2S rRNA gene of
mitochondrial genome was amplified using specific primers and subjected to
restriction digestion using seven restriction enzymes. In RAPD, DNA samples
were amplified using four arbitrary primers. In both studies (morphological and
molecular) Rasbora daniconius (Family Cyprinidae) was used as an out-group.
Flierarchical cluster analysis using all characters (meristic and morphometric) and
only meristic characters separated the six Puntius spp. in a similar manner except
in clustering of P. dorsalis and P. chola. PCA, MDS show that meristic characters
have higher contribution than morphometric characters in separating the six
Puntius spp. Among the seven restriction enzymes five were able to restrict the
amplified fragment. Only one primer was able to produce a RAPD profile. R.
daniconius differ from Puntius spp. at a higher degree in genetically than in
morphologically. P. litleya and P. nigrofascialus show a close relationship
morphologically as well as genetically. P. bimaculalus, P. filamentosus, P.
dorsalis, and P. choia are closely related in their morphology, but P. bimaculalus
and P. dorsalis greatly differ from other two species at molecular level.
