Dezfuli B S, Tinti F
Department of Biology, University of Ferrara, Italy.
J Parasitol. 1998 Aug;84(4):860-2.
Species recognition of acanthocephalans of the genus Neoechinorhynchus (Hamann, 1892) found in the freshwater turtle Trachemys scripta (Wied, 1838) has previously been based primarily on female body and egg morphology. Observed morphological plasticity within and among species may lead to the misclassification of female specimens and leaves males of different species completely indistinguishable. Here, random-amplified polymorphic DNA (RAPD) analysis was used to genetically characterize samples of Neoechinorhynchus pseudemydis (Cable and Hopp, 1954), Neoechinorhynchus emydis (Leidy, 1851), and Neoechinorhynchus emyditoides (Fisher, 1960). Amplifications performed with 3 decamer oligonucleotides showed banding patterns with a few diagnostic fragments that allowed the recognition of N. pseudemydis specimens from those of the N. emydis-N. emyditoides group. No primer gave a species-specific locus that allowed the differentiation of N. emydis from N. emyditoides specimens, suggesting that they could belong to a sole taxon. The species assignment of females of uncertain classification and of males is fully reliable using RAPD markers. Thus, identification of acanthocephalan species by RAPD in the helminth infracommunities could potentially be very useful to determine community structure. RAPD and other polymerase chain reaction-based methods have some practical advantages over multilocus discriminant analysis, such as the ability to use ethanol-stored specimens and small tissue samples of parasites.
此前，对于在淡水龟滑龟（Trachemys scripta，维德，1838年）体内发现的新棘吻虫属（Neoechinorhynchus，哈曼，1892年）棘头虫的物种识别主要基于雌性虫体和虫卵形态。观察到的物种内部和物种之间的形态可塑性可能导致雌性标本的错误分类，并且使得不同物种的雄性标本完全无法区分。在此，随机扩增多态性DNA（RAPD）分析被用于对伪拟新棘吻虫（Neoechinorhynchus pseudemydis，凯布尔和霍普，1954年）、龟新棘吻虫（Neoechinorhynchus emydis，利迪，1851年）以及似龟新棘吻虫（Neoechinorhynchus emyditoides，费舍尔，1960年）的样本进行遗传特征分析。用3种十聚体寡核苷酸进行的扩增显示出具有一些诊断性片段的条带模式，这些片段能够将伪拟新棘吻虫标本与龟新棘吻虫 - 似龟新棘吻虫组的标本区分开来。没有引物能产生一个物种特异性位点来区分龟新棘吻虫和似龟新棘吻虫标本，这表明它们可能属于同一个分类单元。使用RAPD标记对分类不确定的雌性和雄性进行物种归属判定是完全可靠的。因此，在蠕虫小群落中通过RAPD鉴定棘头虫物种对于确定群落结构可能非常有用。相对于多位点判别分析，RAPD和其他基于聚合酶链反应的方法具有一些实际优势，例如能够使用乙醇保存的标本以及寄生虫的小组织样本。
