Phylogeny of the East Asian botiine loaches (Cypriniformes,Botiidae) inferred from mitochondrial cytochrome <Emphasis Type="Italic">b</Emphasis> gene sequences

The Botiinae have traditionally represented a subfamily of the Cobitidae. At present, the classification and phylogenetic relationships of the Botiinae are controversial. To address systematic and phylogenetic questions concerning this group, we sequenced the complete cytochrome b gene from 34 samples, of which 24 represented 13 species of the East Asian botiine fishes, while the other 10 were non-botiine loach species. For the 1140 bp sequences determined, 494 sites were variable ones, of which 424 were parsimony informative. With Myxocyprinus asiaticus as an outgroup, molecular phylogenetic trees were constructed using the neighbor-joining, maximum parsimony, maximum likelihood and Bayesian methods. All molecular phylogenetic trees revealed that botiine fishes form a monophyletic group and are distantly related to other loaches, suggesting that the Botiinae should be placed in their own family. Within the Botiinae, there are three genera; Botia, Parabotia, andLeptobotia, each genus forming a monophyletic group, with the genus Botia as the most ancestral split. Our molecular results are in agreement with morphological analyses of botiines, suggesting that Botia is the ancestral genus, while Leptobotia and Parabotia were resolved as more derived sister groups.     

Isolation and characterization of 39 microsatellite loci in the endangered Japanese loach Leptobotia curta

A microsatellite-enriched genomic library was obtained for the endangered Japanese loach Leptobotia curta, and 39 dinucleotide markers were successfully isolated and characterized. These markers had between one and nine alleles, with expected heterozygosity ranging from 0 to 0.839, in a population from the Lake Biwa-Yodo River system of Japan. Linkage equilibrium was observed in most loci, and only one locus showed significant deviation from Hardy-Weinberg equilibrium. These microsatellite markers will be useful for genetic diversity studies of wild and captive L. curta populations.     

基于线粒体COⅠ基因的沙鳅亚科鱼类DNA条形码及其分子系统发育研究

选择线粒体COⅠ基因作为分子标记,进行沙鳅亚科鱼类（Botiinae）DNA条形码及其分子系统发育研究。研究获得了沙鳅亚科7属19种共131个个体的COⅠ基因序列,利用MEGA5.0软件分析了沙鳅亚科鱼类COⅠ基因的序列特征,计算了种内及种间遗传距离。沙鳅亚科鱼类的分子系统发育关系的重建分别采用NJ法和Bayesian法。研究发现,沙鳅亚科COⅠ基因的碱基组成为: A 24.4%、T 29.5%、G 18.0%、C 28.1%。沙鳅亚科鱼类种内平均遗传距离为0.0020.000,种间平均遗传距离为0.1480.008。DNA条形码研究结果显示,所分析的19种沙鳅鱼类各自分别聚成单系分支,表明COⅠ基因在本研究中具有100%的物种鉴别率。同时,系统发育分析支持各属的单系性,并且结果显示沙鳅亚科鱼类聚为两个分支,其中一支由薄鳅属和副沙鳅属构成,另一分支则包括: （沙鳅属、色鳅属）和 中华沙鳅属、（缨须鳅属、安彦鳅属）。因此,COⅠ基因可以作为有效的分子标记对沙鳅亚科进行DNA条形码研究以及分子系统发育研究。       

广西薄鳅属鱼类一新种(鲤形目,鳅科)

2007年10月,在广西桂平黔江采集到鳅科鱼类6尾,经鉴定为薄鳅属Leptobotia1新种,定名为斑点薄鳅Leptobotia punctatus sp.nov.。新种须3对,眼下刺不分叉,颊部有鳞。这些特征与薄鳅属一致。新种颏下无1对纽状突起,眼小,口角须短,背鳍起点位于腹鳍起点后方等特征与同属的桂林薄鳅L.guilinensis和后鳍薄鳅L.posterodorsalis最为相似。但有如下鉴别特征:新种体侧无垂直条纹,脊椎数目多,腹鳍末端不达肛门等特征,与桂林薄鳅相区别;体侧有斑点,外侧鳃耙数多,体较高,尾鳍深分叉,有3~4道黑色条纹等特征,与后鳍薄鳅相区别。新种仅分布于西江水系黔江。     

沙鳅亚科鱼类线粒体DNA控制区结构分析及系统发育关系的研究

对沙鳅亚科鱼类3属14个代表种的线粒体DNA控制区序列的结构进行了分析。通过与鲤形目鱼类的控制区序列进行比较,将沙鳅亚科鱼类的控制区分为终止序列区、中央保守区和保守序列区三个区域。同时识别了沙鳅亚科中一系列保守序列,并给出了它们的一般形式。以胭脂鱼为外类群,对比条鳅亚科、花鳅亚科、以及平鳍鳅科的代表性种类,采用NJ、MP和ML法构建沙鳅亚科的分子系统树。分子系统发育分析表明,沙鳅亚科为一单系,包括3个属:沙鳅属、副沙鳅属和薄鳅属,各属均构成单系。根据分子系统学、形态学的结果及地理分布推断,沙鳅亚科中沙鳅属可能为最为原始的属,副沙鳅属其次,而薄鳅属最特化。