Echinostomes are a diverse group of digenetic trematodes that are difficult to classify by predominantly traditional techniques and contain many cryptic species. Application of contemporary genetic/molecular markers can provide an alternative choice for comprehensive classification or systematic analysis. In this study, we successfully characterized the intron 5 of domain 1 of the taurocyamine kinase gene (TkD1Int5) of Artyfechinostomum malayanum and the other two species of the 37 collar-spined group, Echinostoma revolutum and Echinostoma miyagawai, whereas TkD1Int5 of Hypoderaeum conoideum cannot be amplified. High levels of nucleotide polymorphism were detected in TkD1Int5 within E. revolutum and E. miyagawai, but not in A. malayanum. Thus, TkD1Int5 can be potentially used as genetic marker for genetic investigation of E. miyagawai and E. revolutum. We therefore used TkD1Int5 to explore genetic variation within and genetic differentiation between 58 samples of E. miyagawai and five samples of E. revolutum. Heterozygosity was observed in 17 and two samples with 16 and three insertion/deletion (indel) patterns in E. miyagawai and E. revolutum, respectively. Heterozygous samples were then cloned and nucleotide sequence was performed revealing the combined haplotypes in a particular sample. Based on nucleotide variable sites (excluding indels), the 72 E. miyagawai and seven E. revolutum haplotypes were subsequently classified. The haplotype network revealed clear genetic differentiation between E. miyagawai and E. revolutum haplogroups, but no genetic structure correlated with geographical localities was detected. High polymorphism and heterogeneity of the TkD1Int5 sequence found in our study suggest that it can be used in subsequent studies as an alternate independent potential genetic marker to investigate the population genetics, genetic structure, and possible hybridization of the other echinostomes, especially the 37 collar-spined group distributed worldwide.

棘皮动物是一组多样化的双基因吸虫，难以通过主要的传统技术进行分类，并且包含许多隐性物种。当代遗传/分子标记的应用可以为综合分类或系统分析提供替代选择。在这项研究中，我们成功地鉴定了Artyfechinostomum malayanum的牛磺胺激酶基因（TkD1Int5）的结构域1的内含子5和37个衣领棘突组的另外两个物种Echinostoma revolutum和Echinostoma miyagawai，而Hypoderaeum conoideum的TkD1Int5不能放大。在E. revolutum和TkD1Int5中检测到高水平的核苷酸多态性。E. miyagawai，但不在A. malayanum中。因此，TkD1Int5可以潜在地用作用于遗传调查遗传标记E. miyagawai和E. Revolutum酒店。因此，我们使用TkD1Int5探索内的遗传变异和58个样品之间的遗传分化E. miyagawai和五个样品E. Revolutum酒店。宫川肠杆菌和大肠埃希氏菌在17个样品中观察到杂合性，两个样品具有16个杂合性，三个插入/缺失（插入/缺失）模式， 分别。然后克隆杂合子样品并进行核苷酸序列分析以揭示特定样品中的组合单倍型。基于（不包括插入缺失）核苷酸变异位点，72个E. miyagawai和七个E. Revolutum酒店单倍型随后分类。单倍型网络揭示了宫崎肠杆菌和革命肠杆菌之间明显的遗传分化单倍体，但未发现与地理区域相关的遗传结构。在我们的研究中发现的TkD1Int5序列具有高度的多态性和异质性，表明它可作为后续的独立潜在遗传标记用于研究人群的遗传，遗传结构以及其他棘皮动物，尤其是37个衣领的杂交。纺集团分布在世界各地。