›› 2017, Vol. 60 ›› Issue (6): 699-709.doi: 10.16380/j.kcxb.2017.06.010

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  1. (首都师范大学生命科学学院, 北京 100048)
  • 出版日期:2017-06-20 发布日期:2017-06-20

To re-construct an evolutionary tree conforming to the natural history process is the ultimate goal of systematic biology (Invited review)

REN Dong   

  1. (College of Life Sciences, Capital Normal University, Beijing 100048, China)
  • Online:2017-06-20 Published:2017-06-20

摘要: 从自然历史的角度,对单系群、特征、系统发育和自然分类系统的概念做出了澄清和解释。自然分类是仅包含单系群全体成员和它们之间亲缘发育关系和自然演化过程的分类。只有包括所有成员在内的单系群才能称为一个自然分类系统。目前生物系统学主要使用分支分析方法重建自然历史演化过程。在编写算法语言和程序时,作者常将注意力集中在形态和分子数据的获得、运算过程和算法的改进,而忽略了支序分类学的简约原则等假设前提和它的理论缺陷。由此在系统发育重建的过程中存在2个常见的误区:(1)在一个单系类群中包括的成员不完全却声称是一个自然系统;(2)将通过数学和程序运算出来的“简约”或最“似然”的亲缘发育关系当作自然系统。自然单系类群往往具有漫长的演化历史,人类无法直接观察和在实验室中重复。利用支序分类原理构建的单系类群的发育关系只是一个单系类群之间的最“简约”或最“似然”的亲缘发育关系,并不能真正反映自然历史的本来面目。古生物学虽然有较好的时空框架,但可提供的特征数量和精度不够。现生生物的各种特征和遗传数据虽然相对充分,但对于具有较长演化历史的类群,由于缺失了大量关键成员,推导出的系统发育关系可能都是并系或复系,无法构成一个自然系统。因此只用现生生物宏观和基因组信息重构具有较长演化历史的生物类群的自然系统是无法实现的。只有利用分子和形态的全证据,从宏观和微观两个层面、古代和现代相结合,采用多种技术和研究手段对一个单系类群的全体成员进行研究,才能真正做到自然分类。在这个过程中可以利用6个原则对分类系统是否符合自然历史发展进行检验。

关键词: 单系, 并系, 分支分析, 自然历史, 自然分类系统

 From the point of view of natural history, both the concepts and characteristics of the monophyletic group, phylogenetic systematics and natural classification system have been clarified. Natural classification system is a taxonomic system and natural evolution process of all members in the monophyletic group and their phylogenetic relationships. Only a monophyletic group including all extinct and extant members can be called a natural taxonomic system. At present, systematic biology mainly uses the cladistic principles and methods to reconstruct an evolutionary tree. During the preparation and application of a variety of system programming languages, researchers often focus on the morphological and molecular data acquisition, and the operating and calculating process, but largely ignore the hypotheses and associated weakness of the parsimony principle and the maximum likelihood or Bayesian inference. There are two common misunderstandings in the process of phylogenetic reconstruction: (1) a monophyletic group is claimed as a natural system due to incomplete selection of ingroup members; (2) a parsimony or likelihood phylogenetic relationship through mathematics and program operations is claimed as a natural evolutionary system. A natural monophyletic group often has a long evolutionary history and cannot be directly observed in nature or repeated in the laboratory. The systematical relationship among a monophyletic group established by cladistics principles is only the maximum parsimony or the likelihood speculation, thus, cannot truly reflect the development process of natural history. Fossils can provide better spatiotemporal framework information, but the number and accuracy of the available features are not sufficient. Living organisms have various abundant characteristic and genetic data. However, due to their long evolutionary history and the lack of a large number of important extinct members, the most deduced phylogenies are paraphyletic group or polyphyletic group and cannot constitute a natural system. It is impossible to construct a natural system of the whole monophyletic group by using only macro and microinformation of extant organisms. With the help of various techniques and research methods, the optimal approach to study a natural system is to combine the morphological and molecular data and integrate the whole ancient and modern members. In this process, six principles can be used to test whether the classification system is consistent with the development of natural history.

Key words: Monophyletic group, paraphyletic group, cladistic analysis, natural history, natural classification system