Department of Genetics, University of Pretoria, Pretoria 0002, South Africa.
Vet Parasitol. 2012 Jun 8;187(1-2):259-66. doi: 10.1016/j.vetpar.2011.12.008. Epub 2011 Dec 19.
The nematode worm Spirocerca lupi has a cosmopolitan distribution and can cause the death of its final canid host, typically dogs. While its life cycle, which involves a coprophagous beetle intermediate host, a number of non-obligatory vertebrate paratenic hosts and a canid final host, is well understood, surprisingly little is known about its transmission dynamics and population genetic structure. Here we sequenced cox1 to quantify genetic variation and the factors that limit gene flow in a 300 km(2) area in South Africa. Three quarters of the genetic variation, was explained by differences between worms from the same host, whereas a quarter of the variation was explained by differences between worms from different hosts. With the help of a newly derived model we conclude that while the offspring from different infrapopulations mixes fairly frequently in new hosts, the level of admixture is not enough to homogenize the parasite populations among dogs. Small infrapopulation sizes along with clumped transmission may also result in members of infrapopulations being closely related.
旋毛线虫（Spirocerca lupi）分布广泛，可导致其最终的犬科宿主（通常是狗）死亡。尽管它的生命周期包括一个食粪甲虫中间宿主、一些非必需的脊椎动物副宿主和一个犬科最终宿主，但人们对其传播动态和种群遗传结构知之甚少。在这里，我们对 cox1 进行了测序，以量化南非一个 300 平方公里区域内的遗传变异和限制基因流动的因素。四分之三的遗传变异可以用来自同一宿主的蠕虫之间的差异来解释，而四分之一的变异可以用来自不同宿主的蠕虫之间的差异来解释。在一个新推导出的模型的帮助下，我们得出结论，虽然来自不同亚种群的后代在新宿主中混合得相当频繁，但混合的程度不足以使犬科寄生虫种群同质化。较小的亚种群规模以及聚集传播也可能导致亚种群成员之间存在密切关系。
