Department of Biology, Texas A&M University, 3258 TAMU, College Station, TX 77843, USA.
Genes (Basel). 2010 Jun 9;1(1):102-23. doi: 10.3390/genes1010102.
Little attention has been given to the role that introgression and hybridization have played in the evolution of parasites. Most studies are host-centric and ask if the hybrid of a free-living species is more or less susceptible to parasite infection. Here we focus on what is known about how introgression and hybridization have influenced the evolution of protozoan and helminth parasites of animals. There are reports of genome or gene introgression from distantly related taxa into apicomplexans and filarial nematodes. Most common are genetic based reports of potential hybridization among congeneric taxa, but in several cases, more work is needed to definitively conclude current hybridization. In the medically important Trypanosoma it is clear that some clonal lineages are the product of past hybridization events. Similarly, strong evidence exists for current hybridization in human helminths such as Schistosoma and Ascaris. There remain topics that warrant further examination such as the potential hybrid origin of polyploid platyhelminths. Furthermore, little work has investigated the phenotype or fitness, and even less the epidemiological significance of hybrid parasites.
人们对基因渐渗和杂交在寄生虫进化中所起的作用关注甚少。大多数研究都以宿主为中心，探讨自由生活物种的杂种是否更容易或更不容易受到寄生虫感染。在这里，我们重点关注基因渐渗和杂交如何影响动物原生动物和蠕虫寄生虫的进化。有报道称，从远缘分类群向顶复门和丝虫类寄生虫中发生了基因组或基因渐渗。最常见的是同种分类群之间潜在杂交的基于遗传的报告，但在某些情况下，需要更多的工作来明确确定当前的杂交。在医学上重要的锥虫中，很明显，一些无性系是过去杂交事件的产物。同样，在人类蠕虫如血吸虫和蛔虫中，也有当前杂交的有力证据。仍有一些值得进一步研究的主题，例如多倍体扁形动物的潜在杂种起源。此外，很少有研究调查杂种寄生虫的表型或适应性，甚至更少研究其流行病学意义。
