DNA Barcoding, Phylogenetics And Phylogeography Of Freshwater Halfbeak Genus Dermogenys (Kuhl & Van Hasselt, 1823) In Sundaland River Basin
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Date
2017-08
Authors
Samsudin, Nurul Farhana
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Publisher
Universiti Sains Malaysia
Abstract
This research was aimed to develop DNA barcodes for the freshwater halfbeak, genus Dermogenys as well as understanding the phylogenetic relationships among Dermogenys species and their phylogeographic distribution in the Sundaland. DNA barcoding based on an approximately 650 bp segment of mitochondrial cytochrome oxidase subunit I (COI) successfully identified and delineated six putative species of genus Dermogenys sampled in Sundaland inland waters involving 290 specimens from 33 localities. Furthermore, barcoding gap analysis, automated barcode gap discovery (ABGD) and phylogenetic tree analyses revealed a new species, Dermogenys sp. and two geographically structured D. bispina populations, D. bispina Sandakan and D. bispina Kudat, potentially composed of two subspecies. In the next part of the study, the phylogenetic relationships and phylogeographic distribution were inferred from two mitochondrial genes, COI and cytochrome b (cyt b) and three single copy anonymous nuclear polymorphic (scnp) loci namely DP21, DP35 and DP37. Phylogenetic relationships of Dermogenys spp. were consistent among the single gene and multigene trees. Relationships from the basal (ancestral) to the internal clusters (descendant) were resolved as follows: D. bruneiensis, D. bispina Kudat, D. bispina Sandakan, D. burmanica, Dermogenys sp., D. siamensis, D. collettei, D. sumatrana and D. pusilla. The multigene analysis suggests that each Dermogenys is monophyletic except for Dermogenys sp. population. The population of Dermogenys sp. from Kuala Sepetang was found to be polyphyletic in the cyt b and scnp trees. This was also found in Sg. Lalang, Alur Itam and Sg. Iyu for the scnp tree. The incongruence of gene tree and multigene/species tree suggests that introgressive hybridization between species that were sympatric resulted in a hybrid species (D. collettei X Dermogenys sp.). This study highlights the necessity of taxonomic appraisal of this genus particularly for D. bispina Sandakan, D. bispina Kudat and Dermogenys sp. groups. The molecular analysis supports that the diversification of genus Dermogenys and phylogeographic distribution were driven by the paleo drainage rearrangement. Most species were also regionally restricted with the exception of D. collettei and D. siamensis which were found in the Malacca Strait+Siam+Mekong and Mekong+Siam respectively, a consequence of their sedentary behaviour. This characteristic also resulted in endemicity of a few species, D. bruneiensis, D. bispina and D. burmanica. Dermogenys sp. were found at the northwest Peninsular Malaysia and northeast Sumatra as well as Isthmus of Kra evidence for the occurrence of an undescribed connectivity at the Kangar-Pattani line that allows fauna transition. Data obtained from this study provides useful guidelines for conservation efforts.
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Keywords
To develop DNA barcodes for , the freshwater halfbeak, genus Dermogenys