Mulvey M, Aho J M, Lydeard C, Leberg P L, Smith M H
Savannah River Ecology Laboratory, University of Georgia, Drawer E, Aiken, SC, 29802, USA.
Evolution. 1991 Nov;45(7):1628-1640. doi: 10.1111/j.1558-5646.1991.tb02668.x.
The population genetic structure of the American liver fluke, Fascioloides magna, and its definitive host the white-tailed deer, Odocoileus virginianus, was examined in South Carolina. Flukes were significantly more common in deer from river-swamp habitat than upland areas and prevalence increased with host age. The distribution of flukes among deer occurred as a negative binomial with the mean dispersion parameter, k, equal to 0.17 and the range from 0.10 to 1.11 within local areas. Significant spatial genetic differentiation was observed for flukes and deer. Patterns of genetic distance in flukes were not concordant with those of the definitive host nor were they related to geographic distance between sample locations. Spatial genetic differentiation among flukes reflected the tendency for individual hosts to harbor multiple individuals from a limited number of parasite clones. The large population size of the parasite and movements of the definitive host tend to counteract factors that lead to spatial differentiation.
在美国南卡罗来纳州，对美洲肝片吸虫（Fascioloides magna）及其终末宿主白尾鹿（Odocoileus virginianus）的群体遗传结构进行了研究。在河流沼泽栖息地的鹿体内，吸虫明显比高地地区的鹿更为常见，且感染率随宿主年龄增加而上升。吸虫在鹿群中的分布呈负二项分布，平均离散参数k等于0.17，在局部地区范围为0.10至1.11。在吸虫和鹿中均观察到显著的空间遗传分化。吸虫的遗传距离模式与终末宿主的模式不一致，也与样本地点之间的地理距离无关。吸虫之间的空间遗传分化反映出单个宿主倾向于携带来自有限数量寄生虫克隆的多个个体。寄生虫的庞大种群数量和终末宿主的移动往往会抵消导致空间分化的因素。
