Department of Biosciences, Faculty of Science, University of Mauritius, Réduit, Mauritius.
Parasitol Res. 2012 Feb;110(2):759-68. doi: 10.1007/s00436-011-2550-x. Epub 2011 Jul 13.
Specimens of Bertiella studeri (Cyclophyllidea, Anoplocephalidae) that have been preserved in ethanol or fixed permanently in formalin for >2 years were used for DNA extraction and molecular characterization. DNA was amplified via PCR from samples collected from different monkey and human hosts using eucestoda-specific primers. Phylogenetic trees were inferred from two sets of sequence data corresponding to the first and second halves of the 18S rDNA gene using two methods (distance-based NJ and maximum parsimony). We found that the second dataset was more suited for inferring phylogeny within the Cyclophyllidea. Both trees show that taxa belonging to the Anoplocephalidae, Hymenolepididae, Davaineidae, and Mesocestoididae are clearly monophyletic within their families and demonstrate sister-group relationships between the Anoplocephalidae and Mesocestoididae, contradicting previous reports of a basal placement of the Mesocestoididae within the Cyclophyllidea. The distance-based phylogeny support a taxonomical classification that groups members of the Bertiella genus, as well as other members of the Anoplocephalidae family, as being most closely related to the Hymenolepididae family and can be used to substantiate the use of uterine morphology as a valid homologous trait for taxonomical and phylogenetic classifications. On the other hand, the parsimony-based phylogeny places the Hymenolepididae closer to the outgroup and shows a closer relationship between the Mesocestoididae and the Taeniidae. This underlies the caution with which gene trees should be interpreted for inferring phylogeny and underlies the need to integrate both morphological and molecular data to represent the actual evolutionary pathway of the species involved.
已保存于乙醇或福尔马林（固定超过 2 年）中的 Bertiella studeri（环口目，膜壳科）标本被用于 DNA 提取和分子特征分析。使用真绦虫特异性引物，从不同猴子和人类宿主采集的样本中通过 PCR 扩增 DNA。使用两种方法（基于距离的 NJ 和最大简约法）从对应于 18S rDNA 基因前半部分和后半部分的两组序列数据推断系统发育树。我们发现第二组数据集更适合在环口目内推断系统发育。两棵树都表明，属于膜壳科、膜头科、Davaineidae 和Mesocestoididae 的分类群在其科内是明显的单系群，并在膜壳科和 Mesocestoididae 之间显示出姐妹群关系，这与 Mesocestoididae 在环口目内的基础位置的先前报告相矛盾。基于距离的系统发育树支持分类学分类，将 Bertiella 属的成员以及其他膜壳科成员与膜头科分组为最密切相关的成员，并且可以用于证实子宫形态作为分类学和系统发育分类的有效同源特征。另一方面，简约法系统发育树将膜头科置于更近的位置，并显示 Mesocestoididae 和 Taeniidae 之间的关系更密切。这强调了在推断系统发育时应谨慎解释基因树，并强调需要整合形态和分子数据以代表所涉及物种的实际进化途径。
