The population history of Garra orientalis (Teleostei: Cyprinidae) using mitochondrial DNA and microsatellite data with approximate Bayesian computation.

BACKGROUND: The South China landmass has been characterized by a complex geological history, including mountain lifting, climate changes, and river capture/reversal events. To determine how this complexity has influenced the landmass's phylogeography, our study examined the phylogeography of Garra orientalis, a cyprinid widely distributed in South China, using sequences from the mitochondrial DNA control region and cytochrome b gene (1887 bp) and polymorphisms of thirteen microsatellite loci. RESULTS: In total, 157 specimens were collected from eight populations. All 88 mtDNA haplotypes were identified as belonging to three major lineages, and these lineages were almost allopatric in their distributions. The results of a statistical dispersal-vicariance analysis suggested that the ancestral populations of G. orientalis were distributed south of the Yunkai Mountains, including on Hainan Island. The mtDNA data revealed a strong relationship between phylogeny and geography. In the microsatellite analysis, a total of 339 alleles with an average of 26 alleles per locus were observed across thirteen microsatellite loci. A clustering algorithm for microsatellite data revealed an admixture-like genetic structure. Although the mtDNA and microsatellite data sets displayed a discordant population structure, the results of an approximate Bayesian computation approach showed that these two markers revealed congruent historical signals. The population history of G. orientalis reflects vicariance events and dispersal related to the complex geological history of South China. CONCLUSION: Our results (i) found that the discordances between mtDNA and microsatellite markers were accounted for by admixtures; (ii) showed that the Wuzhishan and Yinggeling mountain ranges and Qiongzhou Strait were important barriers limiting gene exchange between populations on both sides; (iii) indicated that during glaciation and inter-glacial periods, the strait and continental shelves were exposed and sank, which contributed with the dispersion and differentiation of populations; and (iv) displayed that the admixtures between lineages took place in coastal populations and then colonized the tributaries of the Pearl River.

The complete mitogenome of the oriental sucking barb, Garra orientalis (Cypriniformes, Cyprinidae): repetitive sequences in the control region.

The oriental sucking barb, Garra orientalis, is a small to moderate-sized freshwater fish. In this study, the complete mitochondrial genome of G. oriental was successfully sequenced for the first time with total length of 17,288 bp. The genome structure consists of 13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNA (tRNA) genes and a control region. Moreover, tandem repeat unit ranged from 259 to 260 bp (repeated 3-4 times) was identified in the control region among G. orientalis individuals.

[Morphological differentiation of Garra orientalis(Cyprinidae)among different geographical populations].

Morphological differences were found among specimens of Garra orientalis from Minjiang River, Pearl River, Red River and Hainan Island. To confirm whether the morphological differences among these geographical populations had reached the level of subspecies or species, seventy-two specimens of Garra orientalis were divided into four groups according to the four drainage areas stated above. Ten external morphological characteristics were observed. Thirteen frame characteristics and twenty-three general characteristics were measured and analyzed for multivariate morphometrics. In scatter plots of principal components, the specimens from Hainan Island were relatively concentrated on the scatter plots, but were not completely separated from the other three drainages. The samples from the other three drainages were completely mixed together. These results indicated that the specimens from the different drainages could not be distinguished by morphological comparison and morphometric analysis. Species or subspecies level differentiation of Garra orientalis among geographical populations could instead be studied by molecular biological methods in the future.