Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Werribee, VIC, 3030, Australia.
Parasit Vectors. 2020 Mar 14;13(1):135. doi: 10.1186/s13071-020-4007-5.
Australian marsupials harbour a diverse array of helminth parasites. Despite current attempts to assess the extent of this diversity in macropodid hosts, it has been suggested that unique parasite fauna of Australian wildlife is difficult to document comprehensively due to the common occurrence of cryptic species. This paper assessed genetic variation within Austrostrongylus thylogale Johnston & Mawson, 1940 from the tammar wallaby, Notamacropus eugenii (Gray), and the quokka, Setonix brachyurus (Quoy & Gaimard), from different localities using the molecular characterisation of the internal transcribed spacers (ITS) within the nuclear ribosomal DNA.
Thirty-seven specimens of A. thylogale collected from N. eugenii (from Parndana, Kangaroo Island, South Australia, and Perup, Western Australia) and S. brachyurus (from Wellington Dam, Western Australia) were characterised using a molecular-phylogenetic approach utilising the first (ITS1) and second (ITS2) internal transcribed spacers.
Genetic variation was detected in both ITS1 and ITS2 between specimens of A. thylogale from N. eugenii and S. brachyurus; however, no variation was detected between specimens collected from N. eugenii from Parndana, South Australia, and Perup, Western Australia. Furthermore, the phylogenetic analyses of ITS sequences showed two clades of A. thylogale originating from two hosts, N. eugenii and S. brachyurus, suggesting the presence of cryptic species.
This study provides evidence of genetic variation within A. thylogale based on collections from two different host species. Morphological studies are required to fully confirm the presence of a new species or cryptic species. Further molecular studies using a larger number of specimens are warranted to explore the genetic variation between A. thylogale from different geographical localities.
澳大利亚有袋类动物体内寄生着各种各样的寄生虫。尽管目前有人试图评估巨型有袋目宿主体内寄生虫的多样性，但有人认为，由于隐匿种的普遍存在，澳大利亚野生动物独特的寄生虫区系很难全面记录下来。本文利用核核糖体 DNA 内的内部转录间隔区（ITS）的分子特征，评估了来自塔马尔袋鼠（Notamacropus eugenii）和短尾矮袋鼠（Setonix brachyurus）的 Austrostrongylus thylogale 种内的遗传变异。
从南澳大利亚的帕恩达纳（Parndana）和西澳大利亚的佩鲁普（Perup）采集的 37 只塔马尔袋鼠和来自西澳大利亚惠灵顿大坝（Wellington Dam）的短尾矮袋鼠的 A. thylogale 标本，利用分子系统发育方法，利用第一（ITS1）和第二（ITS2）内部转录间隔区进行了特征描述。
来自 N. eugenii 和 S. brachyurus 的 A. thylogale 标本在 ITS1 和 ITS2 中均检测到遗传变异；然而，来自南澳大利亚的帕恩达纳和西澳大利亚的佩鲁普的 N. eugenii 采集的标本之间没有检测到变异。此外，ITS 序列的系统发育分析显示，A. thylogale 有两个来自两个宿主，N. eugenii 和 S. brachyurus 的分支，表明存在隐匿种。
本研究基于来自两个不同宿主物种的采集提供了 A. thylogale 种内遗传变异的证据。需要进行形态学研究来完全确认新种或隐匿种的存在。进一步使用更多标本的分子研究是有必要的，以探索来自不同地理区域的 A. thylogale 之间的遗传变异。
