| Procambarus clarkii is the one of important commercial freshwater crustacean inChina. Jiangsu province is one of major provinces for farming Procambarus clarkii inChina. It would be very important to study on genetic resources of Procambarusclarkii for the germplasm conservation, utilization, breeding and farming yieldincrease. In this paper,9free stocks were collected(3stocks in Taihu Lake,3stocksin Hongze Lake,1stock in Luoma Lake,1stock in Guchen Lake and1stock inJiangxingzhou) and1stable breeding stocks(Xuyi).12EST-SSR markers wereisolated and characterized in our lab and8EST-SSR were used to analyze the geneticdiversity and stock structure of Procambarus clarkii. Main contents are as follows:1. Screening and analysis of EST-SSR for Procambarus clarkiiThe experiment successfully screened microsatellite primer12pairs and analysisthrough60genomic DNA from Procambarus clarkii. The results show: These12microsatellite loci totally showed polymorphism, the number of alleles per locusbetween3-9; average observed heterozygosity is0.556; average expectedheterozygosity is0.745; all loci showed deviation from Hardy stock-Weinbergequilibrium (P <0.05) and showed high levels of polymorphism information content(PIC>0.5), it can be used in analyzing the genetic structure and diversity.2. Effect of stable breeding in genetic diversity of Procambarus clarkiiIn this research,8microsatellite markers were used to analyze the geneticdiversity of three stocks, included stable breeding stock of Procambarus clarkii inManjianghong, two free stocks in Zhenjiang and Xishunhe.The study showed that allthe eight loci were highly or medium polymorphic. Tests of departures fromHardy-Weinberg equilibrium indicated all64loci in8stocks was significant deviationfrom Hardy-Weinberg Equilibrium after Bonferroni correction. genetic diversity ofthe stocks in Xishenhe was the highest, that of Manjianghong were lowest. FSTandAMOVA analysis across all stocks and loci indicated that there was lowly level ofdivergence among3stocks, FST=0.036(FST<0.05), The UPGMA clustering treebased on genetic distance demonstrated that the free stocks of Xishunhe, Zhenjiangclustered into one group; Manjianghong stable breeding stocks constituted a branch singularly. Overall, the level of genetic diversity in three stocks is high and nosignificant difference among them, there are some genetic differentiation betweenstable breeding stock and free stocks.stock and other stocks.3.Genetic diversity analysis of eight Procambarus clarkii stocks in Jiangsu based onmicrosatelliteGenetic diversity of eight free Procambarus clarkii stocks of Jiangsu Province，they include: three stocks in Taihu Lake (Dapu, Pingwang, Qitang), three stocks inHongze Lake(Guantan, Xishunhe, Taiping), one stock in Guchen Lake(Guchen), onestock in Luoma Lake (Yanghetan) were investigated using8microsatellite DNA loci.The result showed that all the eight loci were highly or medium polymorphic. Tests ofdepartures from Hardy-Weinberg equilibrium indicated all64loci in8stocks wassignificant deviation from Hardy-Weinberg Equilibrium after Bonferroni correctionand most of them has significant heterozygosity deficiency. All of the8stocks showedhigher genetic diversity, and genetic diversity of the stocks in Dapu was the higher,that of Pingwang were lower. FSTand AMOVA analysis across all stocks and lociindicated that there was medium or lowly level of divergence among8stocks, FST=0.126(0.05<FST<0.15), The UPGMA clustering tree based on genetic distancedemonstrated that the stocks of Pingwang, Qitang and Dapu clustered into one group;Taiping, Xishenhe, Guantan converged into another group, GC and YH constituted abranch singularly, we found a significant signal of heterozygote deficiency, indicatinga recent decline in these stocks. Our studies also showed that there were high levels ofgene flow among stocks, and a significant correlation found between genetic distanceand geographic distance (r=0.33, P <0.05). |
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