Morphological and genetic variability of Malaysian channa spp based on morphometric and rapd techniques
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Date
2007
Authors
Mohd Husin, Norainy
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Abstract
A morphometric and genetic study were conducted on six of the seven species that have been documented in Peninsular Malaysia; Channa striata, C. gachua, C. marulioides, C. micropeltes, C. melasoma and C. lucius. Eighteen side view and 11 dorsal view measurements were obtained from 81 individuals. Data was analysed by an analysis of variance, ANOVA and multivariate analyses (Principal Component Analysis- PCA and Discriminant function Analysis- DFA). Based on these statistics, generally all six species were grouped into their own species cluster with minimal overlap. Channa gachua was found to be the most differentiated for both analyses mainly based on size differences along the caudal peduncle (side view) and width of the head (dorsal view). Relationships among the other species were however different between the two analyses. Channa maruloides, C. striata and C. melasoma clustered very closely while C. lucius was a distance away. Channa micropeltes was isolated in terms of body depth from the dorsal to the pectoral fins along the side view. In the dorsal view C. striata, C. lucius with C. micropeltes.were very closely related while C. melasoma was closely related to C. maruloides.
Random Amplified Polymorphic DNA primers (RAPD) were used to estimate genetic variation of six Channa species found in Peninsular Malaysia and their phylogenetic relationship. Ten representatives for each species were analysed except for C. melasoma where only three individuals were obtained. Nine selected RAPD 10-mer nucleotide primers namely AB-2, AB-7, AB-14, AB-18, F2, F3, F10, F16 and F20 were used in this study. The nine primers amplified 83 scorable loci. Results showed fairly high genetic intraspecific variability among species except for C. melasoma. Polymorphism was highest for C. lucius (46.7 %) and lowest for C. melasoma (8.9%) although both were sympatric. Genetic distances between pairwise comparisons were
found to be in the range of 0.6 to 0.7 although a great deal of overlap was observed for between-species comparisons among all the species. The dendogram generated by RAPDistance software revealed that C. gachua was the most basal taxon with C. striata and C. lucius forming the terminal taxa. However, placement of species was slightly different based on the FreeTree software but the dendrogram produced had very low interspecies bootstrap support. Support for the monophyly of each species was, however, excellent at 100%.
The results demonstrated the usefulness of morphometrics in classification of species and defining shape and size differences among the Channa species. On the other hand RAPD can be used to assess DNA polymorphism and intraspecific variability. The applicability of RAPD analysis to systematic studies and phylogenetics should, however, be tested by comparisons with the data from morphological, isozymes variation analysis and DNA sequencing
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Master
Keywords
Science biology , Morphological , genetic variability , Malaysian channa spp , morphometric , rapd techniques