Abstract：
Studying the genetic diversity of nematode parasite populations is crucial to gaining insight into parasite infection dynamics and informing parasite phylogeography. Anisakiasis is a zoonotic disease caused by the consumption of infectious third-stage larvae (L3) of Anisakis spp. carried by marine fish. In the present study, a total of 206 mitochondrial DNA sequences (cytochrome c oxidase 2, cox2) were used to study the genetic diversity, genetic structure, and historical demography of twelve A. pegreffii populations from Trichiurus japonicas along the coast of mainland China and Taiwan. Two distinct evolutionary lineages of A. pegreffii and no significant genealogical structures corresponding to sampling localities suggested that isolation in the marginal seas shaped their patterns of phylogeographic distribution along the coast of mainland China and Taiwan during glaciation with lower sea levels. Furthermore, pairwise FST values and AMOVA did not indicate any significant genetic differentiation among groups with no relation to the geographic area, which might be attributed to fewer barriers to gene flow as well as large population sizes. The results of the neutrality test, mismatch distribution, and Bayesian skyline plot analyses showed that entire population underwent population expansion during the late Pleistocene. Analysis of the demographic history revealed that A. pegreffii underwent historical lineage diversification and admixture due to secondary contact based on ABC analysis. The present research represents the first definitive population structure and demographic history across sampling locations of A. pegreffii along the coast of mainland China and Taiwan.
摘要：
研究线虫寄生虫种群的遗传多样性对于深入了解寄生虫感染动态和告知寄生虫系统发育至关重要。异株病是一种人畜共患疾病，是由食用异株属的感染性第三阶段幼虫（L3）引起的。由海洋鱼类携带。在本研究中,共206个线粒体DNA序列(细胞色素c氧化酶2,cox2)用于研究遗传多样性,遗传结构,以及来自中国大陆和台湾沿海的Trichiurusjaponicas的十二个A.pegreffii种群的历史人口统计。A.pegreffii的两个不同的进化谱系和与采样地点相对应的没有明显的家谱结构表明，在海平面较低的冰期期间，边缘海的隔离改变了它们在中国大陆和台湾沿海的系统地理分布模式。此外，成对FST值和AMOVA没有表明与地理区域无关的群体之间有任何显著的遗传分化，这可能归因于基因流动的障碍较少以及人口众多。中性测试的结果，失配分布，和贝叶斯天际线图分析表明，整个人口在更新世晚期经历了人口膨胀。对人口统计学历史的分析表明，由于基于ABC分析的二次接触，A.pegreffii经历了历史血统的多样化和混合。本研究代表了中国大陆和台湾沿海A.pegreffii采样地点的第一个明确的人口结构和人口统计学历史。
