| Common carp (Cyprinus carpio L.) is one of the major aquaculture species in the world. Inrecent years, large number of researched have been conducted for the molecular breeding ofcommon carp, such as the screening of associated markers, the construction of genetic linkagemap and QTL mapping. The traits contain growth, stress resistance and the physical andchemical properties. However, the screening ang mapping of scale has never been reported. Thescale is an important breeding target, and its variety offers a large number of materials whichcould be applied for the study of genetic basis and molecular breeding in common carp. Thescreening and mapping of the markers associated with scale will promote the development ofmolecular breeding and the research of the molecular mechanism of scale cover.In this study, a total of415microsatellite markers were applied for the screening of scaleassociated markers with a full-sib mapping panel containing96individuals. They were tested in2pedigrees. Besides, a genetic linkage map was conducted, and applied for the mapping of scaleassociated markers. At last, the correlation analysis of microsatellite markers derived from scalegenes with4growth traits in common carp was developed. The main results were listed asfollows:(1)The association analysis identified7SSRs (HLJ2509, HLJ3227, HLJ3675, HLJ3766,HLJ3863, FGFR1, FGFR7) for extremely significant correlation (P<0.01) with scale coverpattern in population1. We also investigated the applicability of those7SSRs in other2populations. The results shown that7SSRs were also extremely significant correlation with scalecover pattern in population2(116individuals)(P<0.01), and6were in population3(57individuals) except for HLJ3227which was significant correlation (P=0.012). In addition, wedetected22genotypes which were specific in individuals with full scale and2genotypes whichwere specific in individuals with missing scale. That difference may be caused by the dominanceof full scale. Among the24specific genotypes,2genotypes are specific of full scale individualsin3populations, others are only in1or2populations. That maybe due to the high mutation rateof microsatellite.(2)A genetic linkage map of common carp was constructed. A total of241microsatellitemarkers were mapped into48linkage groups. All the7markers associated with scale coverpattern were mapped into LG3. Given previous researches and our results, we inferred the likelyoccurrence of gene cluster affecting the scale cover pattern in that linkage group. Because theFGFR1and FGFR7were derived from the gene fgfr1a, fgfr1a should be located in LG3.Under the compare analysis with zebrafish genome,6markers were found to be shown highhomology, among which5were located in chromosome8in zebrafish. Scanning the homology domain and their context,6genes (atoh1a, ptch1, bmp1a, fgfr1a, fgf17, wnt5a) caused ourinteresting. Given previous researches and our results, they were speculated to be likelyassociated with scale forming. They can be considered as candidate genes for the understandingof scale cover mechanism.(3)Aimed to analyze the correlation of scale genes with4growth traits in common carp, total155microsatellite markers were selected from the homologous sequence and its context of ant,eda, edar, fgfr in carp genome, and the population that contains116progenies (population2) wasused to screening the associated markers with body weight, body length, body height and bodythickness. The genetic diversity analysis was also conducted. The results showed that36microsatellite loci were polymorphism, and2-4alleles were detected for each locus, with a totalof86alleles in36loci. The mean number of alleles and the mean effective number of alleleswere2.3889and2.2094, respectively. The mean observed heterozygosity and expectedheterozygosity were0.6245and0.5292, respectively. And the mean polymorphism informationcontent (PIC) was0.4321in36loci, of which23loci were in the moderate level ofpolymorphism (0.25≤PIC<0.5) and13loci were in the high level of polymorphism (PIC≥0.5).The results above indicated the moderate polymorphic level of this population. Consider themicrosatellite markers were located in the genes or their context, this may lead the lowerpolymorphic level. The probability value of chi-square test showed that69%of the36loci havesignificantly deviated from Hardy-Weinberg equilibrium. The artificial selection pressure andself-bred line might contribute to this result. Under the test of General Linear Model (GLM) inSPSS17.0software,10(28%),7(19%),7(19%) and11(31%) microsatellite markers weresignificantly associated with body weight, body length, body height and body thickness,respectively. Those proportions were higher than the results of Gu Ying and Lu Weihua. Elevendominant genotypes were identified via the multiple comparisons. The higher screening rate ofSSR markers tightly linked with growth traits demonstrated that the scale genes might beassociated with growth traits, from the angle of SSR. |
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