【作者】 邹习俊；

【导师】 代应贵；

【作者基本信息】 贵州大学 ， 动物遗传育种与繁殖， 2009， 硕士

【摘要】 四川裂腹鱼(Schizothorax(Racoma)kozlovi)隶属于鲤形目(Cypriniformes)、鲤科(Cyprinidae)、裂腹鱼亚科(Schizothoracinae)、裂腹鱼属(SchizothoraxHeckel)、裂尻鱼亚属(Racoma Mcclelland),分布于我国长江水系雅砻江、金沙江、乌江。四川裂腹鱼肉质细嫩,富含不饱和脂肪酸,为高档食用经济鱼类。近20年来,由于酷渔滥捕、水域污染以及大量水上建筑的出现,该种鱼的资源、自然分布区域日趋减少。目前,在贵州境内乌江水系,四川裂腹鱼的分布区仅限于上游江段,种群数量急剧减少。到目前为止,对四川裂腹鱼的研究主要集中在系统进化与分类、地理分布、繁殖等方面,有关四川裂腹鱼核型以及从分子水平对其种群进行遗传多样性的研究至今尚未见报道。本研究采用活体体内注射PHA法,结果表明:染色体数2n=128,核型公式为:26m+22sm+24st+56t,染色体臂数(NF)176。初步认为四川裂腹鱼可能是多倍化了的六倍体,在裂腹鱼亚科中进化地位比较低,较原始。线粒体DNA(mtDNA)是分子生物学研究的一个热门领域,已经被广泛地应用于鱼类进化生物学和群体遗传学研究。本实验首次采用mtDNA分子标记方法对四川裂腹鱼遗传多样性进行研究。利用PCR扩增和直接测序法分析了乌江流域四川裂腹鱼32尾样品,对mtDNA控制区(D-Loop)3’端共计464bp的碱基序列进行了测定分析,共发现9个变异位点,占分析位点总数的1.94%,定义了9种单倍型。核苷酸多样度(π)为0.00324,平均核苷酸差异数(K)为1.500,单倍型间平均遗传距离(P)为0.0060。用单倍型间的遗传距离构建的NJ系统树和UPGMA系统树,分属2个支系。目前四川裂腹鱼乌江种群遗传多样性较低。更多还原

【Abstract】 Schizothorax(Racoma) kozlovi belongs to Schizothorax,Schizothoracinae, Cyprinidae and Cypriniformes.It is distributed in the Yalong River,Jinsha River and Wujiang River of the Yangtze River systems in China.In the past 20 years, over-fished,water pollution and dams over the rivers have resulted in the gradually decline of the fish resources and natural distribution.At present,Schizothorax (Racoma) kozlovi,the population of which shows sharp decline,distributed only in the upstream of the Wujiang river.So far,the research on Schizothorax(Racoma) kozlovi focuses on phylogenetic classification,geographical distribution,reproduction and so on.It has not been reported about the karyotype and genetic diversity of this species.In this paper,the karyotype of Schizothorax(Racoma) kozlovi was studied by the method of PHA(phytohaemagglutinin) injection in vivo.The result showed that the diploid chromosome number of Schizothorax(Racoma) kozlovi is 128,it’s karyotype formula is 26m+22sm+24st+56t,NF=176.It was considered that Schizothorax (Racoma) kozlovi is likely to be hexaploid that already is diploidizated.It is infered that Schizothorax(Racoma) kozlovi is the very primitive group in Schizothoracinae. Recently,the study on mitochondrial DNA(mtDNA) is a hot field in molecular biology research,mitochondrial DNA as an ideal genetic marker has been successfully applied to the research of the evolutionary biology of fishes and the population genetics.A total of 9 variable sites(accounted for1.94%of the analysis variable sites) were detected.By sequencing,the 464 bp from 3 end of mtDNA D-loop in the 32 specimen of the species,which were collected from the Wujiang River in Guizhou,9 haplotypes were defined,the nucleotide diversity(π) is 0.00324, the average number of nucleotide diffences(K) is 1.500,and the average genetic distance(P) between the haplotypes of the samples is 0.0060.The NJ phylogenetic tree and UPGMA phylogenetic tree of the 9 haplotypes belong to 2 branches.It is extremely necessary to protect the population of Schizothorax(Racoma) kozlovi from the Wujiang River.更多还原