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目的对长江下游江西、安徽和江苏3省湖北钉螺的不同地理种群进行群体遗传结构分析,以探讨rDNA ITS分子标记在钉螺扩散路径监测中的应用价值。方法采集3省9个种群的钉螺样本,提取基因组DNA,PCR特异性扩增rD NA ITS基因并克隆测序,统计分析群体间的遗传分化系数(Fst)、遗传距离和种群遗传多样性等参数,利用单倍型构建家系网络图。结果9个种群共获得有效序列93条,检测到78个单倍型,平均单倍型多样性、核苷酸多样性分别为0.988和0.012 88,表明钉螺种群的遗传多样性水平较高;其遗传变异主要来自群体内,种群间遗传距离为0.001 6~0.002 3,显示钉螺种群间遗传分化程度较高;家系网络图显示所有单倍型虽可形成3个主要的家系分支,但各地理种群在家系网络图中无明显分化。结论长江下游江西、安徽和江苏3省沿长江分布的湖北钉螺群体遗传多样性主要存在个体间,群体间未形成明显的遗传分化。rDNA ITS分子标记在钉螺扩散路径监测中的应用价值值得进一步探讨。
Objective To analyze the population genetic structure of different geographical populations of snails in Jiangxi, Anhui and Jiangsu provinces in the lower reaches of the Yangtze River so as to explore the value of rDNA ITS markers in the monitoring of snail diffusion pathways. Methods Snail specimens from nine populations of three provinces were collected and genomic DNA was extracted. ITS gene of rD NA was amplified by PCR and cloned and sequenced. The genetic differentiation coefficient (Fst), genetic distance and genetic diversity among populations were statistically analyzed. Using Haplotype to Build Family Network Map. Results Nine of the nine populations were successfully sequenced and 78 haplotypes were detected. The average haplotype diversity and nucleotide diversity were 0.988 and 0.012 88, respectively, indicating that the genetic diversity of Oncomelania snails populations was high. The genetic variation mainly came from within the population, and the genetic distance between populations was 0.001 6-0.0023, indicating a high degree of genetic differentiation among snails. The pedigree network showed that all the haplotypes formed three major families, but the geographical populations In the family network diagram no significant differentiation. Conclusion The genetic diversity of the snail population in Hubei Province along the Yangtze River in Jiangxi, Anhui and Jiangsu provinces in the lower reaches of the Yangtze River mainly exists among individuals, but no obvious genetic differentiation has been found among the populations. The value of rDNA ITS molecular markers in snail diffusion pathological monitoring is worth further exploration.