Snps Detection Of High Density Lipoprotein Binding Protein Gene(HBP) And Cathepsin B(CTSB) And The Association With Growth Traits In Largemouth Bass (Micropterus Salmoides)

The largemouth bass (Micropterus salmoides), common name Californian bass,was subordinate to Perciformes, Porcoidei, Cehtrachidae, Micropterus. It’s one ofimportant cultivated fish in China. In recent twenty years, production units do notobserve the rules of breeding, picking the small and early mature individuals as theparent, along with the small founder population and not introduce protospecies regularly,result in low genetic diversity and production performance degradation which haveseriously affected the benefit of largemouth bass culture. So it’s necessary to carry outthe fish breed improvement programme. Marker assistant selection (MAS) which hasthe high stability and the information content, is influenced slightly by theenvironmental condition and is an effective way to selective breeding. Based on theEST-SNP database of largemouth bass (Micropterus salmoides), High densitylipoprotein binding protein (HBP) gene and Cathepsin B（CTSB）gene were chosen ascandidate markers to value the association between SNP and growth traits.1.SNPs Detection of High Density Lipoprotein Binding Protein Gene(HBP) and ItsAssociation with Growth TraitsHigh density lipoprotein binding protein (HBP) plays an important role in fatmetabolism. Lipid is indispensable to fish energy material, It is very important forcarnivorous fish which has low efficiency to use carbohydrate, especially.The singlenucleotide polymorphism(SNP) in HBP gene may affect the fat metabolism, andcorrelated to growth traits. Study the association between the SNP and growth traits canprovide candidate markers for marker-assisted selection. In this study, partial genomicfragments of HBP gene were amplified based on the sequences of one available contig in the EST-SNP database of largemouth bass (Micropterus salmoides). Three singlenucleotide polymorphism(SNP) mutations were identified after sequencing the PCRproducts of twenty individuals (H1:G+2782T, H2:T+2817C, H3:G+2857A), which werelocated in3′non-coding region. For the three SNPs, the genotype and gene frequency of165largemouth bass were further assayed with the method of SnaPshot. Geneticstructure was analyzed by POPGENE32software. A general linear model(GLM) wasused in the correlation analysis between HBP gene SNPs and growth traits. The resultsshowed that three locus were in Hardy-Weinberg equilibrium. The sites of H1and H2formed two haplotypes (A and B) and three genotypes (AA, AB, and BB). The sites ofH1, H2and H3formed six diplotypes(D1, D2, D3, D4, D5and D6). Associationanalysis showed that the individual SNP was not significantly associated with growthtraits. The body weight and total length of genotype BB and AB were significantlydifferent (P<0.05). The body weight and total length of diplotypes D2and D6weresignificantly different (P<0.05). The SNP markers founded in HBP gene was candidategenetic markers, which could be used in future breeding programs of largemouth bass.2. SNPs Detection of Cathepsin B Gene(CTSB) and Its Association with GrowthTraitsCathepsin B（CTSB） is a lysosomal cysteine endoproteinase which participatein many physiological and pathological events and to hydrolysis many animal proteinand vegetable protein, so it is a topic gene to research animal carcass and meat qualitytraits. Study the association between the SNP and growth traits can provide candidatemarkers for marker-assisted selection. A candidate gene was choose from the EST-SNPdatabase of largemouth bass. Partial genomic fragments of CTSB gene were amplifiedbased on the sequences of one available contig in the EST-SNP database of largemouthbass (Micropterus salmoides). A single nucleotide polymorphism(SNP) mutation wasidentified after sequencing the PCR products of twenty individuals (H:C+598G), whichwas a missense mutation and caused for arginine mutate to glycine, formed the threegenotypes CC, CG and GG. The165largemouth bass was random selected, whichhatched in the same time and cultivated in the same pond. For the SNP, the genotype and gene frequency of165largemouth bass were further assayed with the method ofSnaPshot. Genetic structure was analyzed by POPGENE32software. A general linearmodel(GLM) was used in the correlation analysis between CTSB gene SNP and growthtraits. The results showed that the heterozygosity observed(HO) was0.4727, thepolymorphism information content(PIC) was0.3593, and the loci was inHardy-Weinberg equilibrium. The frequencies of GG, CG and CC were12.12%,47.27%and40.61%, and the frequencies of G and C were35.76%and64.24%respectively.Association analysis showed that the average phenotypic value of the traits body weight,total length, body depth, caudal peduncle length and caudle peduncle depth were GG＜GC＜CC. The body weight of genotype CC was significantly weightier than genotypeGG(P<0.05). Our data suggested a significant association between genetic variationsin the largemouth bass CTSB gene and growth traits. These results indicated that theSNP markers founded in CTSB gene was candidate genetic markers, which could beused in future breeding programs of largemouth bass. The SNP markers founded inCTSB gene was candidate genetic markers, which could be used in future breedingprograms of largemouth bass.In this research, based on the EST-SNP database of largemouth bass, Highdensity lipoprotein binding protein (HBP) gene and Cathepsin B（CTSB）gene werechosen as candidate markers，4SNPs locus were found. Valuing the association betweenSNP and growth traits, two advantage genetypes was found as markers. Our datasuggested a significant association between genetic variations in the largemouth bassHBP gene and growth traits, so as to CTSB gene. These results indicated that the SNPsmarkers founded in HBP gene and CTSB gene were candidate genetic markers, whichcould be used in future breeding programs of largemouth bass.