Patterson C
Department of Palaeontology, British Museum (Natural History), London, England.
Mol Biol Evol. 1988 Nov;5(6):603-25. doi: 10.1093/oxfordjournals.molbev.a040523.
Hypotheses of homology are the basis of comparative morphology and comparative molecular biology. The kinds of homologous and nonhomologous relations in classical and molecular biology are explored through the three tests that may be applied to a hypothesis of homology: congruence, conjunction, and similarity. The same three tests apply in molecular comparisons and in morphology, and in each field they differentiate eight kinds of relation. These various relations are discussed and compared. The unit or standard of comparison differs in morphology and in molecular biology; in morphology it is the adult or life cycle, but with molecules it is the haploid genome. In morphology the congruence test is decisive in separating homology and nonhomology, whereas with molecular sequence data similarity is the decisive test. Consequences of this difference are that the boundary between homology and nonhomology is not the same in molecular biology as in morphology, that homology and synapomorphy can be equated in morphology but not in all molecular comparisons, and that there is no detected molecular equivalent of convergence. Since molecular homology may reflect either species phylogeny or gene phylogeny, there are more kinds of homologous relation between molecular sequences than in morphology. The terms paraxenology and plerology are proposed for two of these kinds--respectively, the consequence of multiple xenology and of gene conversion.
同源性假说是比较形态学和比较分子生物学的基础。经典生物学和分子生物学中的同源和非同源关系类型，是通过可应用于同源性假说的三项检验来探究的：一致性、关联性和相似性。这三项检验同样适用于分子比较和形态学研究，并且在每个领域中它们区分出八种关系类型。本文对这些不同的关系进行了讨论和比较。形态学和分子生物学中的比较单位或标准有所不同；在形态学中是成体或生命周期，但对于分子而言则是单倍体基因组。在形态学中，一致性检验在区分同源性和非同源性时起决定性作用，而对于分子序列数据，相似性是决定性检验。这种差异带来的结果是，分子生物学中同源性与非同源性之间的界限与形态学中的不同，同源性和共近裔性状在形态学中可以等同，但并非在所有分子比较中都如此，并且未检测到与趋同现象等效的分子情况。由于分子同源性可能反映物种系统发育或基因系统发育，所以分子序列之间的同源关系类型比形态学中的更多。本文针对其中两种关系类型分别提出了“旁 xenology”和“全 xenology”这两个术语，它们分别是多重 xenology 和基因转换的结果。 （注：原文中“xenology”可能是特定领域的专业术语，未找到确切对应中文，保留原文以待进一步确认其准确含义）
