Schierwater Bernd, Kolokotronis Sergios-Orestis, Eitel Michael, DeSalle Rob
ITZ, Ecology and Evolution, Tierärztliche Hochschule Hannover, D-30559 Hannover, Germany.
Commun Integr Biol. 2009 Sep;2(5):403-5. doi: 10.4161/cib.2.5.8763.
For many familiar with metazoan relationships and body plans, the hypothesis of a sister group relationship between Diploblasta and Bilateria1 comes as a surprise. One of the consequences of this hypothesis-the independent evolution of a nervous system in Coelenterata and Bilateria-seems highly unlikely to many. However, to a small number of scientists working on Metazoa, the parallel evolution of the nervous system is not surprising at all and rather a confirmation of old morphological and new genetic knowledge.2-4 The controversial hypothesis that the Diploblasta and Bilateria are sister taxa is, therefore, tantamount to reconciling the parallel evolution of the nervous system in Coelenterata and Bilateria. In this addendum to Schierwater et al.1 we discuss two aspects critical to the controversy. First we discuss the strength of the inference of the proposed sister relationship of Diploblasta and Bilateria and second we discuss the implications for the evolution of nerve cells and nervous systems.
对于许多熟悉后生动物关系和身体结构的人来说，双胚层动物和两侧对称动物之间存在姐妹群关系的假说令人惊讶。这一假说的一个结果——腔肠动物和两侧对称动物的神经系统独立进化——在许多人看来极不可能。然而，对于少数研究后生动物的科学家来说，神经系统的平行进化一点也不奇怪，反而证实了古老的形态学知识和新的遗传学知识。因此，双胚层动物和两侧对称动物是姐妹分类群这一有争议的假说，等同于调和腔肠动物和两侧对称动物神经系统的平行进化。在Schierwater等人的这篇附录中，我们讨论了争议的两个关键方面。首先，我们讨论双胚层动物和两侧对称动物拟姐妹关系推断的力度，其次，我们讨论对神经细胞和神经系统进化的影响。
