Giribet Gonzalo
Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA.
Philos Trans R Soc Lond B Biol Sci. 2008 Apr 27;363(1496):1513-22. doi: 10.1098/rstb.2007.2241.
The advent of numerical methods for analysing phylogenetic relationships, along with the study of morphology and molecular data, has driven our understanding of animal relationships for the past three decades. Within the protostome branch of the animal tree of life, these data have sufficed to establish its two main side branches, the moulting Ecdysozoa and the non-moulting Lophotrochozoa. In this review, I explore our current knowledge of protostome relationships and discuss progress and future perspectives and strategies to increase resolution within the main lophotrochozoan clades. Novel approaches to coding morphological characters are needed by scoring real observations on species selected as terminals. Still, methodological issues, for example, how to deal with inapplicable characters or the coding of absences, may require novel algorithmic developments. Taxon sampling is another key issue, as phyla should include enough species so as to represent their span of anatomical disparity. On the molecular side, phylogenomics is playing an increasingly important role in elucidating animal relationships, but genomic sampling is still fairly limited within the lophotrochozoan protostomes, for which only three phyla are represented in currently available phylogenies. Future work should therefore concentrate on generating novel morphological observations and on producing genomic data for the lophotrochozoan side of the animal tree of life.
在过去三十年里，用于分析系统发育关系的数值方法的出现，以及形态学和分子数据的研究，推动了我们对动物关系的理解。在动物生命树的原口动物分支中，这些数据足以确立其两个主要的旁支，即蜕皮动物蜕皮动物和非蜕皮的冠轮动物。在这篇综述中，我探讨了我们目前对原口动物关系的了解，并讨论了在主要冠轮动物类群中提高分辨率的进展、未来前景和策略。需要通过对作为终端选择的物种的实际观察进行评分，来采用新的方法对形态特征进行编码。然而，方法学问题，例如如何处理不适用的特征或缺失的编码，可能需要新的算法开发。分类群抽样是另一个关键问题，因为门应该包括足够多的物种，以代表它们解剖学差异的范围。在分子方面，系统发育基因组学在阐明动物关系方面发挥着越来越重要的作用，但在冠轮动物原口动物中，基因组抽样仍然相当有限，在目前可用的系统发育中，只有三个门有代表。因此，未来的工作应该集中在产生新的形态学观察结果，以及为动物生命树的冠轮动物一侧生成基因组数据。
