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目的分析在山东微山湖地区长期放养的湖北钉螺(Oncomelania hupensis)群体与其来源地江苏省长江江滩钉螺群体之间的基因差异。方法收集江苏省扬州市江都区、仪征市和丹阳市、南京市六合区的长江钉螺以及山东省济宁市微山湖独山岛的钉螺。微山湖区放养的钉螺来自于扬州市江都区,放养时间为10年(至2014年)。选择A18、C22、T4-33、T6-17等4对微卫星位点对钉螺群体进行PCR扩增,分析各钉螺群体的等位基因数(Na)、期望杂合度(He)、观察杂合度(Ho)和群体间遗传差异平均数等指标,并进行分子变异方差分析(AMOVA),用非加权组平均法(UPGMA)和邻接法(NJ)构建系统进化树描述群体遗传分化及聚类情况。使用Mantel检验探讨遗传距离与地理距离的相关性。结果本研究收集5个钉螺群体共103只钉螺。江都、仪征、丹阳、六合、微山湖群体的Na分别为7.50、12.50、10.00、11.50和12.75;Ho分别为0.16、0.27、0.17、0.30和0.22;He分别为0.81、0.91、0.84、0.90和0.92。微山湖群体的3个遗传多样性指标均在较高水平,提示有较好的遗传多样性,但与其他群体差异无统计学意义(P>0.05)。微山湖与江都钉螺群体间遗传差异平均数最小(0.79),丹阳群体与其他群体之间差异较大,为0.87~0.97。AMOVA分析的遗传变异主要来源于钉螺个体间(占92.50%)。NJ和UPGMA系统进化树显示,江都和微山湖的钉螺群体聚为一支,仪征和六合的钉螺群体聚为一支,丹阳钉螺群体与其他4个群体聚为一支。Mantel检验显示遗传距离与地理距离没有相关性。结论江苏省长江钉螺群体与微山湖钉螺群体基因多样性均较高,微山湖地区放养的钉螺与来源地的长江钉螺群体尚未出现明显遗传分化。
Objective To analyze the genetic differences between Oncomelania hupensis populations and the snail populations in the Yangtze River beach, Jiangsu Province, which were long-term stocked in Weishan Lake, Shandong Province. Methods The snails were collected from Jiangdu District of Yangzhou City, Yizheng City and Danyang City, Liuhe District of Nanjing City, and Dushan Island, Weishan Lake, Jining City, Shandong Province. Weishan Lake stocking snail from Yangzhou City Jiangdu District, stocking time is 10 years (2014). Four pairs of microsatellite loci such as A18, C22, T4-33 and T6-17 were selected for PCR amplification of the snail population. The number of alleles (Na), the expected heterozygosity (He), the observed heterozygosity (Ho), and the average number of genetic differences between populations were calculated and analyzed by molecular variance analysis of variance (AMOVA). The phylogenetic tree was constructed by UPGMA and NJ to describe the population genetic differentiation and clustering . Mantel test was used to explore the relationship between genetic distance and geographical distance. Results In this study, 103 snails were collected from 5 snails. Na of Jiangdu, Yizheng, Danyang, Liuhe and Weishanhu were 7.50,12.50,10.00,11.50 and 12.75 respectively; Ho were 0.16,0.27,0.17,0.30 and 0.22 respectively; He was 0.81,0.91,0.84,0.90 and 0.92. The three genetic diversity indicators of Weishan Lake population were all at high level, suggesting a good genetic diversity, but no significant difference with other groups (P> 0.05). The average genetic difference between Weishan Lake and Jiangdu population was the lowest (0.79), and the difference between Danyang population and other populations was 0.87 ~ 0.97. The genetic variation of AMOVA was mainly from individuals of Oncomelania (92.50%). The phylogenetic trees of NJ and UPGMA showed that the snail populations in Jiangdu and Weishan Lake were clustered together, the snail populations in Yizheng and Luhe were clustered into one group, and the snail populations in Danyang were clustered together with the other four populations. The Mantel test showed no correlation between genetic distance and geographic distance. Conclusion The genomic DNAs of Oncomelania hupensis and Weishan Lake in Jiangsu Province are relatively high. The genetic diversity of Oncomelania hupensis in the Weishan Lake area and the Yangtze River snail population in the source area have not yet been obvious.