FUNCTIONAL EVOLUTIONARY DIVERGENCE OF PROTEOLYTIC-ENZYMES AND THEIR INHIBITORS
FUNCTIONAL EVOLUTIONARY DIVERGENCE OF PROTEOLYTIC-ENZYMES AND THEIR INHIBITORS
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DOI：
10.1016/0968-0004(89)90159-x
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发表时间：
1989-08-01
影响因子：
13.8
通讯作者：
DARBY, NJ
中科院分区：
文献类型：
--
作者：
CREIGHTON, TE;DARBY, NJ
Fig. 1.用假设的基因系统树说明直系同源基因和旁系同源基因之间的差异。图中显示，祖先基因在祖先物种中复制，产生两个基因，A和B，它们可能获得略微不同的功能。在稍后的时间，祖先物种分离成两个不同的物种，1和lI，并且基因A和B都保留在每个新物种中。随后在物种H中，基因A被再次复制，产生第三个基因C。在这段时间里，每个基因谱系至少会积累中性突变，因此目前所有的基因及其蛋白质产物都是可以区分的。所有的基因和蛋白质都是同源的，但只有两对AI，A，t和BI，B是直向同源的。所有其他成对比较都是旁系同源的。基因也可能在分化过程中丢失，这可能使其难以区分旁系同源和直系同源比较。例如，如果基因Ai 1在进化上已经丢失，或者只是不知道，那么可以得出结论，基因Ai和C是直交的。
Fig. 1. Illustration of the difference between orthologous and paralogous gene,~ a, using a hypothetical gene phylogenetic tree. The ancestral gene is illustrated being duplicated in the ancestral species, to produce two genes, A and B, which probably acquire slightly different functions. At a later time, the ancestral species separates into two different species, 1 and lI, and both genes A and B are retained in each of the new species. Subsequently in species H, gene A is illustrated as being duplicated again to produce a third gene, C. During all this time, each gene lineage will be accumulating at least neutral mutations, so that at the present time all the genes and their protein products will be distinguishable. All the genes and proteins are homologous, but only the two pairs AI, A, t, and BI, B, are orthologous. All other pairwise comparisons are paralogous. Genes may also be lost during divergence, which can make it difficult to distinguish between paralogous and orthologous comparisons. For example, if gene A i1 has been lost evolutionarily, or simply is not known, it might be concluded that genes A i and C, are orthologous.