Phylogenetics and population genetics of benzimidazole resistance alleles in different Haemonchus species and introgression of such alleles between different species

寄生线虫出现抗药性是对畜牧业和人类健康的重大威胁。血吸虫是一种以血液为食的寄生线虫，是世界上最重要的牛、绵羊和山羊寄生虫之一，也是胃肠道寄生虫的重要模式。主要感染绵羊和山羊的螺旋体对驱虫药的抗药性很普遍，这使得控制变得越来越困难，在某些情况下是不可能的。胎盘丝虫是一种密切相关的物种，主要感染牛，那里的抵抗力开始出现，但尚未进行任何详细的研究。我尤其对两个项目感兴趣。首先，我想调查苯并咪唑耐药等位基因在血吸虫属不同物种中的患病率、序列多样性和进化关系。这应该提供有关耐药性如何出现和传播的重要信息。其次，我想调查抗药性基因从一种寄生虫物种传递到另一种寄生虫物种的可能性，因为这将是牛寄生虫控制的一个特别严重的问题。这在理论上是可能的，因为在实验室里，可以通过成虫的实验杂交产生可生育的后代。此外，这两个物种的混合感染在自然界中通常发生在牛和羊身上。我计划利用分子遗传学和群体遗传学分析研究苯并咪唑耐药基因的种间杂交和导入，对这两个物种的实验混合感染和野外自然寄生虫种群进行分析。

The emergence of drug resistance in parasitic nematodes is a major threat both to the livestock industry and to human health. Species of Haemonchus are blood-feeding parasitic nematodes that are among the most economically important parasites of cattle, sheep and goats worldwide and are important models for gastrointestinal parasitism. Anthelmintic resistance of H. contortus, which predominantly infects sheep and goats, is widespread and is making control increasingly difficult and in some cases impossible. H. placei is a closely related species that predominantly infects cattle where resistance is beginning to emerge but yet to be studied in any detail. In particular I am interested in two projects. First, I want to investigate the prevalence, sequence diversity and evolutionary relationships of benzimidazole drug resistance alleles in different species of the genus Haemonchus. This should provide important information about how drug resistance emerges and spreads. Second, I want to investigate the potential of resistance genes passing from one parasite species to another as this would be a particularly serious issue for parasite control in cattle. This is theoretically possible for H. contortus and H. placei since fertile progeny can be produced by experimental crosses of the adult parasites in the laboratory. Furthermore, co-infections with both species commonly occur in both cattle and sheep in nature. I plan to investigate inter-species hybridization and introgression of benzimidazole drug resistance genes using molecular genetic and population genetic analysis on both experimental co-infections with the two species and on natural parasite populations in the field.