Sandland Gregory J, Foster Alice V, Zavodna Monika, Minchella Dennis J
Department of Biological Sciences, Purdue University, West Lafayette, IN 47907-2054, USA.
Parasitol Res. 2007 Sep;101(4):1083-9. doi: 10.1007/s00436-007-0593-9. Epub 2007 Jun 13.
Genetic variability is often predicted to enhance host fitness in the face of parasitism, yet this idea is rarely tested in an experimental setting, particularly with animal hosts. To assess this question, we used a relatively resistant line of snail hosts (Biomphalaria glabrata) to generate inbred and outcrossed progeny that were then either exposed or sham-exposed to the trematode parasite, Schistosoma mansoni. Results showed no difference in prevalence between the groups; however, large differences appeared in other host life history traits, particularly reproduction. Outcrossed progeny produced large numbers of eggs relative to inbred progeny especially in the face of infection. Furthermore, eggs produced by outcrossed snails took less time to hatch and exhibited greater hatching success compared to their inbred counterparts. Parasite reproduction demonstrated the opposite trend, with fewer parasites emerging from outcrossed snails compared to inbred individuals. This work shows that the introduction of genetic variation into inbred snail populations can have important implications for the viability of host populations and disease transmission.
通常预计遗传变异性会在面对寄生现象时提高宿主的适应性，但这一观点很少在实验环境中得到验证，尤其是在动物宿主方面。为了评估这个问题，我们使用了具有相对抗性的蜗牛宿主品系（光滑双脐螺）来产生近交和杂交后代，然后将这些后代要么暴露于曼氏血吸虫吸虫寄生虫，要么进行假暴露。结果显示两组之间的患病率没有差异；然而，在其他宿主生活史特征方面出现了很大差异，尤其是繁殖方面。相对于近交后代，杂交后代产生了大量的卵，尤其是在受到感染的情况下。此外，与近交蜗牛产生的卵相比，杂交蜗牛产生的卵孵化所需时间更短，孵化成功率更高。寄生虫繁殖呈现出相反的趋势，与近交个体相比，从杂交蜗牛中出现的寄生虫更少。这项工作表明，将遗传变异引入近交蜗牛种群可能对宿主种群的生存能力和疾病传播产生重要影响。
