Characterization of a highly conserved microsatellite marker with utility potentials in cyprinid fishes

A microsatellite locus, MFW1, originating from common carp is highly conserved in flanking nucleotides but variable in repeat length in some fishes from different families of the Cypriniformes. This orthologous locus is polymorphic in approximately 58% of the species tested in the order and is inherited by Mendelian law. It proved to be a potentially good marker in population genetics and in the cyprinid species-breeding programme in which no microsatellite markers were available.

Genetic structure of Chinese sucker population Myxocyprinus asiaticus in the Yangtze River based on mitochondrial DNA marker

The sequencing analysis of the mitochondrial DNA control region (mtCR DNA) was performed to assess the genetic divergence and population structure of the Chinese sucker Myxocyprinus asiaticus (Cypriniformes Catostomidae) using four sample lots from natural populations of the Yangtze River. The mtCR DNA sequences of approximately 920 base pairs were obtained. A total of 223 nucleotide positions were polymorphic, and these defined 39 haplotypes. Of the 39 haplotypes, 37 (90%) were not shared, and among the populations as a whole there was little sharing of haplotypes. The average haplotype diversity (0.958) and the average nucleotide diversity (0.052) indicated a higher level of genetic diversity of Chinese sucker through the river. Analysis of molecular variation (AMOVA) of data revealed significant partitioning of variance (P<0.001) among populations (60.29%), and within populations (39.71%). The topology according to the neighbor joining and maximum parsimony methods showed mosaic composition of the 39 haplotypes, suggesting that the populations wore not completely divergent. The pairwise F statistic values, however, indicated that the population structuring existed to some extent among the geographic populations. There was a positive relationship between the aquatic distance and the genetic distance (Fst) among the populations (P<0.05). Based on our data, it is suggested that genetic drift, gene flow, and stochastic events are the possible factors influencing the population structure and genetic variation.

Sequence variations of the S7 ribosomal protein gene in primitive cyprinid fishes: Implication on phylogenetic analysis

Cyprinidae is the largest fish family in the world and contains about 210 genera and 2010 species. Appropriate DNA markers must be selected for the phylogenetic analyses of Cyprinidae. In present study, the 1st intron of the S7 ribosomal protein (r-protein) gene is first used to examine the relationships among cyprinid fishes. The length of the 1st intron obtained by PCR amplification ranges from 655 to 859 by in the 16 cyprinid species investigated, and is 602 by in Myxocyprinus asiaticus. Out of the alignment of 925 nucleotide sites obtained, the parsimony informative sites are 499 and occupy 54% of the total sites. The results indicate that the 1st intron sequences of the S7 r-protein gene in cyprinids are rich in informative sites and vary remarkably in sequence divergence from 2.3% between close species to 66.6% between distant species. The bootstrap values of the interior nodes in the NJ (neighbor-joining) and MP (most-parsimony) trees based on the present S7 r-protein gene data are higher than those based on cytochrome b and the d-loop region respectively. Therefore, the 1st intron sequences of the S7 r-protein gene in cyprinids are sensitive enough for phylogenetic analyses, and the 1st intron is an appropriate genetic marker for the phylogenetic reconstruction of the taxa in different cyprinid subfamilies. However, attempts to discuss whether the present S7 r-protein gene data can be applied to the phylogeny of the taxa at the level of the family or the higher categories in Cypriniformes need further studies.

鲤科野鲮亚科第二类群的系统分类及重要类群的系统发育检验

Zhang 等(2000)根据口唇部结构把鲤形目Cypriniformes 鲤科Cyprinidae 野鲮 亚科Labeoninae 鱼类分为三个类群。其中第二个类群鱼类的特征是吻皮发达向 腹面下包、上唇退化、下唇向复杂的形态演变，有的形成似吸盘状的雏形构造。 在整理广西鱼类标本时，发现来自广西桂林大埠的十余尾标本不能归到野鲮亚科 任何属中，在这里建立一个新属-狭吻鱼属(Stenorhinchus)。狭吻鱼属的口唇部结 构具有野鲮亚科第二类群鱼类的特征。本研究的目的是为了探讨狭吻鱼属的有效 性及其在野鲮亚科第二类群中的系统位置。传统的观点（张鹗，1998）认为异华 鲮属Parasinilabeo 与唇鱼属Semilabeo、泉水鱼属Pseudogyrinocheilus 的亲缘关 系较近，苏瑞凤（2001）认为异华鲮属与华缨鱼属、直口鲮属构成一个单系群， 本研究的另一目的是要探讨异华鲮属在野鲮亚科中的分类地位，同时描述了异华 鲮属一新种-长鳍异华鲮（Parasinilabeo longiventralis）。 基于外部形态和骨骼特征，利用分支系统学原理和方法对野鲮亚科第二类群 鱼类进行系统发育研究。选择野鲮亚科第二类群的直口鲮属（Rectoris）、穗唇鲃 属（Crossocheilus）、角鱼属（Akrokolioplax）、华缨鱼属（Sinocrossocheilus）、拟 缨鱼属（Pseudocrossocheilus）、异华鲮属（Parasinilabeo）、唇鱼属（Semilabeo）、 泉水鱼属（ Pseudogyrinocheilus ） 和第一类群的鲮(Cirrhinus) 、舌唇鱼 （Lobocheilus）、脂孟加拉鲮（Bangana）作为内群，以鲃亚科的刺鲃(Spinibarbus caldwelli)、大鳞高须鱼（Hypsibarbus vernayi）作为外群。利用外群比较法选取 性状，进行编码后建立一个性状状态矩阵。然后应用软件MacClade4.0 和Paup4.0 进行分析。本研究选取61 个性状来构建系统发育树。系统发育树结果表明：（1） 野鲮亚科第二类群的鱼类构成一个单系群，在这里把它们命名为穗唇鲃组；（2） 狭吻鱼属是个有效属，应置于野鲮亚科第二类群并与唇鱼属、泉水鱼属的亲缘关 系最近；（3）异华鲮属与狭吻鱼属、唇鱼属、泉水鱼属的亲缘关系较密切，在4 属之中，它是较早分化出来的类群； （4）宽唇华缨鱼和三齿华缨鱼不聚成姐妹 群，华缨鱼属不构成单系群；（5）直口鲮和宽唇华缨鱼的分类地位不稳定，需要 今后进一步的分子生物学研究确认。

岭鳅属(Oreonectes)鱼类的分类整理

本研究对岭鳅属鱼类进行了分类整理。对目前鉴定出的岭鳅属鱼类6 个种63 尾鱼类标本的28 个可量性状和6 个可数性状进行了测量和计数；对分类学上存 在疑问的种的测量数据进行了主成分分析。结合测量、计数以及主成分分析的结 果，并应用系统发育物种概念，评价岭鳅属鱼类物种的有效性，并描述岭鳅属鱼 类两新种。主要结论如下： 1. 岭鳅属的主要鉴别特征为：前、后鼻孔分开一短距离，前鼻孔位于一个管状 系统中，管状系统的末端延长成须状；骨质鳔囊为敞开型；上颌无齿状突起。 借此特征岭鳅属鱼类与条鳅亚科（Nemachilinae）其它属级类群完全区分开 来。 2. 小眼岭鳅（Oreonectes microphthalmus）采自广西都安、罗城。根据其尾鳍叉 形，眼睛退化仅残留一黑色素眼点，全身裸露无鳞，头部的眶下管孔为3+0 以及眶上管孔为7，将小眼岭鳅描述成岭鳅属一新种。 3. 多斑岭鳅（Oreonectes polystigmus）采自广西桂林大埠。根据其侧线不完全， 仅在头部后方有6 个侧线孔，头部的眶上管孔为7，眶下管孔为4+7 以及身 体布满不规则的斑点或斑块而将其描记成岭鳅属一新种。 4. 分布于广西都安的透明岭鳅（Oreonecetes translucens）与分布于贵州荔波的 长须盲副鳅（Paracobitis longibarbatus）、荔波盲条鳅（Nemacheilus liboensis） 和荔波岭鳅（Oreonectes liboensis）是同一物种，并根据其前鼻孔与后鼻孔紧 相邻、骨质鳔囊侧囊的后壁为骨质、雄性胸鳍外侧鳍条增宽变硬的特征，将 它们归属为高原鳅属（Triplophysa），有效名称为长须盲高原鳅（Triplophysa longibarbatus）。