Abstract：
BACKGROUND: In China, the plerocercoid of the cestode Spirometra mansoni is the main causative agent of human and animal sparganosis. However, the population genetic structure of this parasite remains unclear. In this study, we genotyped S. mansoni isolates with the aim to improve current knowledge on the evolution and population diversity of this cestode.
METHODS: We first screened 34 perfect simple sequence repeats (SSRs) using all available omic data and then constructed target sequencing technology (Target SSR-seq) based on the Illumina NovaSeq platform. Next, a series of STRUCTURE. clustering, principal component, analysis of molecular variance and TreeMix analyses were performed on 362 worm samples isolated from 12 different hosts in 16 geographical populations of China to identify the genetic structure.
RESULTS: A total of 170 alleles were detected. The whole population could be organized and was found to be derived from the admixture of two ancestral clusters. TreeMix analysis hinted that possible gene flow occurred from Guizhou (GZ) to Sichuan (SC), SC to Jaingxi (JX), SC to Hubei (HB), GZ to Yunnan (YN) and GZ to Jiangsu (JS). Both neighbor-joining clustering and principal coordinate analysis showed that isolates from intermediate hosts tend to cluster together, while parasites from definitive hosts revealed greater genetic differences. Generally, a S. mansoni population was observed to harbor high genetic diversity, moderate genetic differentiation and a little genetic exchange among geographical populations.
CONCLUSIONS: A Target SSR-seq genotyping method was successfully developed, and an in-depth view of genetic diversity and genetic relationship will have important implications for the prevention and control of sparganosis.
METHODS: We first screened 34 perfect simple sequence repeats (SSRs) using all available omic data and then constructed target sequencing technology (Target SSR-seq) based on the Illumina NovaSeq platform. Next, a series of STRUCTURE. clustering, principal component, analysis of molecular variance and TreeMix analyses were performed on 362 worm samples isolated from 12 different hosts in 16 geographical populations of China to identify the genetic structure.
RESULTS: A total of 170 alleles were detected. The whole population could be organized and was found to be derived from the admixture of two ancestral clusters. TreeMix analysis hinted that possible gene flow occurred from Guizhou (GZ) to Sichuan (SC), SC to Jaingxi (JX), SC to Hubei (HB), GZ to Yunnan (YN) and GZ to Jiangsu (JS). Both neighbor-joining clustering and principal coordinate analysis showed that isolates from intermediate hosts tend to cluster together, while parasites from definitive hosts revealed greater genetic differences. Generally, a S. mansoni population was observed to harbor high genetic diversity, moderate genetic differentiation and a little genetic exchange among geographical populations.
CONCLUSIONS: A Target SSR-seq genotyping method was successfully developed, and an in-depth view of genetic diversity and genetic relationship will have important implications for the prevention and control of sparganosis.
摘要：
背景：在中国，曼氏孢子虫的plerocercoid是人和动物裂头虫病的主要病原体。然而,这种寄生虫的种群遗传结构仍不清楚。在这项研究中,我们对S.mansoni分离株进行了基因分型，目的是提高对这种昆虫的进化和种群多样性的最新认识。
方法：我们首先使用所有可用的组学数据筛选了34个完美的简单重复序列（SSR），然后基于IlluminaNovaSeq平台构建了靶测序技术（TargetSSR-seq）。接下来,一系列的结构。聚类，主成分，对从中国16个地理种群的12个不同宿主中分离的362个蠕虫样品进行了分子方差分析和TreeMix分析，以鉴定其遗传结构。
结果：共检测到170个等位基因。整个种群可以被组织起来，并且被发现来自两个祖先集群的混合。TreeMix分析表明，可能发生从贵州（GZ）到四川（SC）的基因流动，SC到Jaingxi(JX)，SC到湖北(HB)，GZ到云南（YN）和GZ到江苏（JS）。近邻聚类和主坐标分析都表明，来自中间宿主的分离株倾向于聚集在一起，而来自确定宿主的寄生虫显示出更大的遗传差异。一般来说,观察到S.mansoni种群具有高度的遗传多样性，地理种群之间适度的遗传分化和少量的遗传交换。
结论：成功开发了TargetSSR-seq基因分型方法，并深入了解遗传多样性和亲缘关系，对预防和控制叉头虫病具有重要意义。
方法：我们首先使用所有可用的组学数据筛选了34个完美的简单重复序列（SSR），然后基于IlluminaNovaSeq平台构建了靶测序技术（TargetSSR-seq）。接下来,一系列的结构。聚类，主成分，对从中国16个地理种群的12个不同宿主中分离的362个蠕虫样品进行了分子方差分析和TreeMix分析，以鉴定其遗传结构。
结果：共检测到170个等位基因。整个种群可以被组织起来，并且被发现来自两个祖先集群的混合。TreeMix分析表明，可能发生从贵州（GZ）到四川（SC）的基因流动，SC到Jaingxi(JX)，SC到湖北(HB)，GZ到云南（YN）和GZ到江苏（JS）。近邻聚类和主坐标分析都表明，来自中间宿主的分离株倾向于聚集在一起，而来自确定宿主的寄生虫显示出更大的遗传差异。一般来说,观察到S.mansoni种群具有高度的遗传多样性，地理种群之间适度的遗传分化和少量的遗传交换。
结论：成功开发了TargetSSR-seq基因分型方法，并深入了解遗传多样性和亲缘关系，对预防和控制叉头虫病具有重要意义。
