Polymorphism Of SSR And Analysis With Growth Traits In Silurus Lanzhouensis

Lanzhou catfish(Silurus lanzhouensis),also known as the Yellow River catfish,which is the unique largescale commercial fish in the upper reaches of the Yellow River.It is of high nutritio nal and commercialimportance,and thus has recently been the focus of public attention.Howev er,due to the excessive expl-oitation and habitat destruction,its natural populations have shrunk to increasingly smaller sizes,and have been listed among the endangered species in China.Pres ently,the primary problems exist in S.lanzhouensis culturing trade are decreasing populationsize and low breeding selection level.Therefore,in order to lay a theoretical foundation for compre hensive selection of the Lanzhou catfish,by using the EST-SSR Marking technique,genetic div ersity of Lanzhou catfish was been analyzed.coding sequences(CDS)of RPL15,Myf5 in Lanz hou catfish were cloned and analyzed using RT-PCR,TA-cloning and nucleotide sequencing tec hniques in this study.Expression patterns of these two genes in eight different tissues amongdif ferent individual sex Lanzhou catfish were investigated using real-time fluorescent quantitativeme thod.With the methods of sequencing and single-strand conformation polymorphism,SNPs of My oD and MyoG gene were detected and molecular markersrelated to growth traits were found,wh ich benefit for the protection and breeding of Lanzhou catfish resources.The main results of th ese studies are as follows:(1)218 of them contained EST microsatellites,GenBank Accession Number:JZ84579-JZ845687,JZ845227-JZ845367.Besides,81 EST sequences were been contained,GenBank Accession Number:JZ845478-JZ84559.According to unique flanking sequences of each motif,299 pairs E ST-SSR primers were designed and synthesized 53 pairs of them to PCR,22 pairs EST-SSR pr-imers can gain unique target PCR products,11 polymorphic EST-SSR were screened out by P-AGE-silver staining.(2)The complete coding sequence(CDS)of RPL15 genes of Lanzhou catfish generation w as cloned,and it's sequence is 615 bp(GenBank:KT1969343),which were constituted polypept ide composed by 355 amino alkaline residues.By using fluorescence quantitative PCR,the RPL 15 gene was mainly expressed inbrain tissue and liver tissue,and the brain tissue and liver tiss ue were significantly higher thanother tissues(P<0.01).Female was significantly higher than ma le(P<0.05)in the brain tissue.The section coding sequence(CDS)of rVMyf5 genes of Lanzhou catfish generation was clon ed,and it's sequence is 477 bp(GenBank:KT580948),which were constituted polypeptide com posed by 122 amino acidic residues.By using fluorescence quantitative PCR,the Myf5 gene wa s mainly expressed in muscle tissue.Male was significantly higherthan female(P<0.05)in the muscle tissue.(3)MyoD gene found only one mutant G250A in the first exon.MyoD were three genotype s(AA,BBand AB).The phenotype of AB was the highest and BB was the lowest in weight,body heightphenotype.The three phenotype was significant(P<0.05).The three genotypes from high to lowfor the AA,AB,BB in body length phenotype.There was a significant difference ph enotypes(P<0.05).MyoG gene found only one mutant C213T in the first exon.MyoG were three genotypes(CC,EE and EC).The phenotype of AB was the highest and BB was the lowest in weight,bo dy height phenotyp-e.The effects of three different genotypes were EE,EC,CC on high body weight,body length,and body height phenotype.The EE genotype was significantly higher than other two genotyp-es(P<0.05).