Lewis F A, Knight M, Richards C S
Biomedical Research Institute, Rockville, MD 20852, USA.
Mem Inst Oswaldo Cruz. 1997 Sep-Oct;92(5):661-2. doi: 10.1590/s0074-02761997000500019.
Development of Schistosoma mansoni in the intermediate host Biomphalaria glabrata is influenced by a number of parasite and snail genes. Understanding the genetics involved in this complex host/ parasite relationship may lead to an often discussed approach of introducing resistant B. glabrata into the field as a means of biological control for the parasite. For the snail, juvenile susceptibility to the parasite is controlled by at least four genes, whereas one gene seems to be responsible for adult nonsusceptibility. Obtaining DNA from F2 progeny snails from crosses between parasite-resistant and -susceptible snails, we have searched for molecular markers that show linkage to either the resistant or susceptible phenotype. Both restriction fragment length polymorphism (RFLP) and random amplified polymorphic DNA (RAPD) approaches have been used. To date, using a variety of snail and heterologous species probes, no RFLP marker has been found that segregates with either the resistant or susceptible phenotype in F2 progeny snails. More promising results however have been found with the RAPD approach, where a 1.3 kb marker appears in nearly all resistant progeny, and a 1.1 kb marker appears in all susceptible progeny.
曼氏血吸虫在中间宿主光滑双脐螺体内的发育受到多种寄生虫和螺类基因的影响。了解这种复杂的宿主/寄生虫关系中所涉及的遗传学知识，可能会引出一种常被讨论的方法，即向野外引入具有抗性的光滑双脐螺，作为对该寄生虫的一种生物防治手段。对于这种螺类而言，其幼虫对寄生虫的易感性至少由四个基因控制，而一个基因似乎决定了成虫的不易感性。我们从抗寄生虫和易感染寄生虫的螺类杂交产生的F2代子代螺中提取DNA，寻找与抗性或易感性表型相关的分子标记。我们使用了限制性片段长度多态性（RFLP）和随机扩增多态性DNA（RAPD）两种方法。迄今为止，使用多种螺类和异源物种探针，尚未在F2代子代螺中发现与抗性或易感性表型共分离的RFLP标记。然而，RAPD方法取得了更有前景的结果，其中一个1.3 kb的标记几乎出现在所有抗性子代中，一个1.1 kb的标记出现在所有易感性子代中。
