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目的 比较湖北省庙河沿岸地区钉螺CO1基因序列的差异 ,探讨光壳螺与肋壳螺差异的原因。方法 在该地区选 7个点 (上游 4个点 ,下游 3个点 )采集钉螺 ,用CTAB法提取钉螺基因组DNA ,PCR方法扩增CO1基因 ,纯化后测序 ,运用ESEE软件排序并比较变异位点 ,观察各点钉螺的CO1基因单倍体型 ,运用PHYLIP软件计算遗传距离 ,绘制基因进化树。结果 获得CO1基因大小为 638bp ,上游和下游累积变异位点数分别为 2 9和 46,两者差异具有显著性 ;各采集点内钉螺按变异位点多少可分为两组 ;各采集点间存在有相同的基因单倍体型 ;上游和下游螺群之间的遗传距离为 0 0 2 2 1± 0 0 10 5 ;在FITCH绘制的基因进化树上 ,上游和下游地区钉螺交错分布在同一亚种不同的两个分支中。结论 在不同的生态环境下 ,下游地区钉螺CO1基因的变异强度比上游大 ;庙河各采集点螺群间存在一定的基因流动 ;庙河地区螺群属湖北钉螺湖北亚种 (O h hupensis) ,可能存在着两种不同进化速率的螺群。
Objective To compare the differences of the CO1 gene sequences of Oncomelania snails in the coastal area of the Mia River in Hubei Province and to explore the reasons for the differences in the CO1 gene sequences. Methods The snails were collected at 7 points (4 points upstream and 3 points downstream) in the area. The snail genomic DNA was extracted by CTAB method. The CO1 gene was amplified by PCR and sequenced. ESEE software was used to rank and compare the variation sites The CO1 gene haplotypes of the snails were observed. The genetic distance was calculated using PHYLIP software and the phylogenetic tree was drawn. Results The size of CO1 gene was 638bp and the number of accumulated mutation sites was 29 and 46, respectively. There was a significant difference between the two groups. The number of mutants in each collection site was divided into two groups according to their number of variation sites. The genetic distance between upstream and downstream spiral groups was 0 0 2 2 1 ± 0 0 10 5. On the phylogenetic tree drawn by FITCH, the snails in the upstream and downstream regions were staggered in the same subspecies In two different branches. Conclusions In different ecological environments, the variation intensity of CO1 gene in Oncomelania snails in the downstream area is larger than that in the upper reaches. Some gene flow exists between the spirochetes in the Miahe area and the Ophionous snub- , There may be two different rates of evolution of the spiral group.