Morphological and genetic variability of Malaysian channa spp based on morphometric and RAPD techniques
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Date
2007-02
Authors
Moho Husin, Norainy Binti
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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 micrope/tes 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 1 O-rner
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
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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 morphometries 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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Keywords
Malaysian channa SPP , Morphometric and RAPD techniques