Nadler S A, Lindquist R L, Near T J
Department of Biological Sciences, Northern Illinois University, DeKalb 60115-2861, USA.
J Parasitol. 1995 Jun;81(3):385-94.
Isoenzyme and random amplified polymorphic DNA (RAPD) markers were used to characterize the genetics of geographic variation among population samples of Ascaris suum from midwestern localities. Independent estimates of fixation indices (FST) based on isoenzyme and RAPD markers showed the same general patterns of differentiation and substantial statistical correlation (r = 0.70). Of the total estimated gene diversity, 9.4% (isoenzyme) and 9.2% (RAPD) was distributed among infrapopulations. Geographic localities accounted for 7.8% (isoenzyme) and 6.2% (RAPD) of the total gene diversity. Only infrapopulations from a single farm were characterized by low fixation indices (isoenzyme and RAPD FST < 0.05). Isoenzyme and RAPD markers revealed moderate genetic differentiation among infrapopulations and localities, which indicates significant population subdivision among A. suum from farms within geographic regions. Departures from random mating were revealed by deficiencies of heterozygotes within infrapopulations and by high positive values of FIS among and between infrapopulations. The average inbreeding (FIS) coefficient among all infrapopulations was 0.22. Thus, the genetic composition of these A. suum infrapopulations, whether from a general geographic region of a single farm, was not consistent with a model of random recruitment from a larger panmictic pool of parasite life cycle stages.
同工酶和随机扩增多态性DNA（RAPD）标记被用于表征来自中西部地区的猪蛔虫种群样本中地理变异的遗传学特征。基于同工酶和RAPD标记的固定指数（FST）的独立估计显示出相同的总体分化模式和显著的统计相关性（r = 0.70）。在总估计基因多样性中，9.4%（同工酶）和9.2%（RAPD）分布在亚种群之间。地理区域占总基因多样性的7.8%（同工酶）和6.2%（RAPD）。只有来自单个农场的亚种群具有低固定指数（同工酶和RAPD的FST < 0.05）。同工酶和RAPD标记揭示了亚种群和地理区域之间存在中等程度的遗传分化，这表明在地理区域内的农场中，猪蛔虫的种群细分显著。亚种群内杂合子的缺乏以及亚种群之间和亚种群内部FIS的高正值表明存在偏离随机交配的情况。所有亚种群的平均近交系数（FIS）为0.22。因此，这些猪蛔虫亚种群的遗传组成，无论是来自单个农场的一般地理区域，都不符合从更大的随机交配寄生虫生命周期阶段库中随机招募的模型。
