Evolutionary change of the numbers of homeobox genes in bilateral animals
Evolutionary change of the numbers of homeobox genes in bilateral animals
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DOI：
10.1093/molbev/msi229
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发表时间：
2005-12-01
影响因子：
10.7
通讯作者：
Nei, M
中科院分区：
文献类型：
--
作者：
Nam, J;Nei, M
同源异型盒基因的保守性或多样性是导致不同生物体某些形态或生理特征相似性和变异性的重要原因。为了深入了解双侧动物同源盒基因的进化模式，我们研究了双侧动物在进化过程中同源盒基因数量的变化。我们分析了从秀丽隐杆线虫到人类的11种双边动物中编译的2，031个同源结构域序列。我们用改良的协调树方法进行的系统发育分析表明，在双侧动物的共同祖先中至少有大约88个同源盒基因。其中约有50-60个基因在所研究的11个物种中各留下了至少一个后代基因，这表明约有30-40个基因以谱系特异的方式丢失。虽然在每个物种中存活下来的祖先基因数量相似，但脊椎动物谱系通过复制获得的基因比无脊椎动物谱系多得多，导致脊椎动物中有200多个同源异型盒基因，无脊椎动物中约有100个同源异型盒基因。在这些基因复制之后，每个谱系中也丢失了大量旧的复制基因。由于许多旧的重复基因丢失了，很可能在基因丢失的时候，丢失的基因已经与其他基因组区分开来。我们的结论是，在双边动物的表型性状的进化变化的同源框基因的获得和丢失是重要的。
It has been known that the conservation or diversity of homeobox genes is responsible for the similarity and variability of some of the morphological or physiological characters among different organisms. To gain some insights into the evolutionary pattern of homeobox genes in bilateral animals, we studied the change of the numbers of these genes during the evolution of bilateral animals. We analyzed 2,031 homeodomain sequences compiled from 11 species of bilateral animals ranging from Caenorhabditis elegans to humans. Our phylogenetic analysis using a modified reconciled-tree method suggested that there were at least about 88 homeobox genes in the common ancestor of bilateral animals. About 50-60 genes of them have left at least one descendant gene in each of the 11 species studied, suggesting that about 30-40 genes were lost in a lineage-specific manner. Although similar numbers of ancestral genes have survived in each species, vertebrate lineages gained many more genes by duplication than invertebrate lineages, resulting in more than 200 homeobox genes in vertebrates and about 100 in invertebrates. After these gene duplications, a substantial number of old duplicate genes have also been lost in each lineage. Because many old duplicate genes were lost, it is likely that lost genes had already been differentiated from other groups of genes at the time of gene loss. We conclude that both gain and loss of homeobox genes were important for the evolutionary change of phenotypic characters in bilateral animals.