无肠目（无肠扁形动物门，扁形动物门）的分子系统学及其与形态学的一致性

Molecular systematics of the Acoela (Acoelomorpha, Platyhelminthes) and its concordance with morphology.

作者信息

Hooge Matthew D, Haye Pilar A, Tyler Seth, Litvaitis Marian K, Kornfield Irv

机构信息

Department of Biological Sciences, The University of Maine, Orono, ME 05569-5751, USA.

出版信息

Mol Phylogenet Evol. 2002 Aug;24(2):333-42. doi: 10.1016/s1055-7903(02)00236-1.

DOI:10.1016/s1055-7903(02)00236-1

PMID:12144766

Abstract

The phylogenetic relationships of the lower worm group Acoela were investigated using newly obtained nuclear 18S rDNA sequences from 16 acoels in combination with 16 acoel sequences available on GenBank from other laboratories. Parsimony and maximum likelihood analyses of the molecular data supported the concept that the Acoela is monophyletic; however, the gene tree produced by these analyses conflicts with the current taxonomic system for the Acoela in several family-level groupings. Most notable is the apparent polyphyly of the largest family of acoels, the Convolutidae. DNA analysis grouped together species of small-bodied convolutids in one clade, while large-bodied convolutids grouped in a separate clade with other large-bodied acoels. Despite such conflicts, the branching pattern in the gene tree is well supported by morphological characters of sperm and body-wall musculature.

摘要

利用新获得的16种无肠目动物的核18S rDNA序列，并结合其他实验室在GenBank上可获得的16种无肠目动物序列，对低等蠕虫类群无肠目动物的系统发育关系进行了研究。对分子数据的简约分析和最大似然分析支持了无肠目动物是单系群的概念；然而，这些分析产生的基因树在几个科级分类中与当前的无肠目动物分类系统存在冲突。最值得注意的是，无肠目动物中最大的科——旋肠科明显是多系的。DNA分析将小型旋肠科动物的物种归为一个分支，而大型旋肠科动物则与其他大型无肠目动物归为一个单独的分支。尽管存在这些冲突，但基因树中的分支模式得到了精子和体壁肌肉组织形态特征的有力支持。