Fasciola hepatica demonstrates high levels of genetic diversity, a lack of population structure and high gene flow: possible implications for drug resistance.
Fasciola hepatica demonstrates high levels of genetic diversity, a lack of population structure and high gene flow: possible implications for drug resistance.
复制标题
Fasciola Hepatica表现出高水平的遗传多样性，缺乏种群结构和高基因流量：对耐药性的可能影响。
DOI：
10.1016/j.ijpara.2016.09.007
复制
发表时间：
2017-01
影响因子：
4
通讯作者：
Hodgkinson J
中科院分区：
文献类型：
--
作者：
Beesley NJ;Williams DJ;Paterson S;Hodgkinson J
自体受精确实发生，但在肝片吸虫的田间种群中很少见。一些宿主携带基因型相同的寄生虫（克隆）。克隆的存在与克隆扩增和聚集传播一致。84%的1579 F. hepatica具有独特的基因型，表明具有较高的遗传多样性。我们发现高基因流，没有种群结构和低自花受精率。肝片形吸虫是一种对畜牧业具有重要经济意义的吸虫寄生虫，是一种重新出现的人畜共患病，对人类健康构成威胁。世界各地的肝病流行区。耐药性是当前和未来控制F.虽然这种寄生虫的生物学特性影响了抗药性的发展和传播，但人们对这种寄生虫的生物学特性知之甚少。考虑到F.由于Hepatica可以自花受精并因此近亲繁殖，因此存在更大的群体分化的可能性和隐性等位基因（例如抗药性基因）聚集在一起的可能性增加。这可能是由蜗牛中间宿主内的克隆扩张和牧场上相同基因型的寄生虫聚集而造成的。另一方面，通常发生在英国的动物大规模迁移可能会促进高水平的基因流动，防止种群分化。我们发现克隆寄生虫具有相同的多位点基因型的61%的主机。尽管如此，1579个成虫中有84%具有独特的多位点基因型，这支持了F.肝细胞群我们的分析表明，自交率不超过2%，这表明这种多样性部分是由于F。肝细胞杂交受精。最后，虽然我们确定了高的遗传多样性在一个给定的主机，有很少的证据表明，从不同的主机群体之间的分化，表明一个单一的panmictic人口。这意味着，一旦这些出现，驱虫药抗性基因有可能通过肝吸虫种群迅速传播。
Self-fertilisation does occur but is rare in field populations of Fasciola hepatica. Some hosts harboured genotypically identical parasites (clones). The presence of clones is consistent with clonal expansion and clumped transmission. 84% of 1579 F. hepatica had unique genotypes, indicating high genetic diversity. We found high gene flow, no population structure and low self-fertilisation rate. Fasciola hepatica, the liver fluke, is a trematode parasite of considerable economic importance to the livestock industry and is a re-emerging zoonosis that poses a risk to human health in F. hepatica-endemic areas worldwide. Drug resistance is a substantial threat to the current and future control of F. hepatica, yet little is known about how the biology of the parasite influences the development and spread of resistance. Given that F. hepatica can self-fertilise and therefore inbreed, there is the potential for greater population differentiation and an increased likelihood of recessive alleles, such as drug resistance genes, coming together. This could be compounded by clonal expansion within the snail intermediate host and aggregation of parasites of the same genotype on pasture. Alternatively, widespread movement of animals that typically occurs in the UK could promote high levels of gene flow and prevent population differentiation. We identified clonal parasites with identical multilocus genotypes in 61% of hosts. Despite this, 84% of 1579 adult parasites had unique multilocus genotypes, which supports high levels of genotypic diversity within F. hepatica populations. Our analyses indicate a selfing rate no greater than 2%, suggesting that this diversity is in part due to the propensity for F. hepatica to cross-fertilise. Finally, although we identified high genetic diversity within a given host, there was little evidence for differentiation between populations from different hosts, indicating a single panmictic population. This implies that, once those emerge, anthelmintic resistance genes have the potential to spread rapidly through liver fluke populations.