Pébusque M J, Coulier F, Birnbaum D, Pontarotti P
Institut de Cancérologie et d'Immunologie de Marseille, INSERM U 119, France.
Mol Biol Evol. 1998 Sep;15(9):1145-59. doi: 10.1093/oxfordjournals.molbev.a026022.
Paralogous genes from several families were found in four human chromosome regions (4p16, 5q33-35, 8p12-21, and 10q24-26), suggesting that their common ancestral region underwent several rounds of large-scale duplication. Searches in the EMBL databases, followed by phylogenetic analyses, showed that cognates (orthologs) of human duplicated genes can be found in other vertebrates, including bony fishes. In contrast, within each family, only one gene showing the same high degree of similarity with all the duplicated mammalian genes was found in nonvertebrates (echinoderms, insects, nematodes). This indicates that large-scale duplications occurred after the echinoderms/chordates split and before the bony vertebrate radiation. It has been suggested that two rounds of gene duplication occurred in the vertebrate lineage after the separation of Amphioxus and craniate (vertebrates + Myxini) ancestors. Before these duplications, the genes that have led to the families of paralogous genes in vertebrates must have been physically linked in the craniate ancestor. Linkage of some of these genes can be found in the Drosophila melanogaster and Caenorhabditis elegans genomes, suggesting that they were linked in the triploblast Metazoa ancestor.
在四个人类染色体区域（4p16、5q33 - 35、8p12 - 21和10q24 - 26）中发现了来自几个家族的旁系同源基因，这表明它们的共同祖先区域经历了几轮大规模复制。在EMBL数据库中进行搜索，随后进行系统发育分析，结果表明人类复制基因的同源物（直系同源物）可以在其他脊椎动物中找到，包括硬骨鱼类。相比之下，在每个家族中，在非脊椎动物（棘皮动物、昆虫、线虫）中仅发现一个与所有复制的哺乳动物基因具有相同高度相似性的基因。这表明大规模复制发生在棘皮动物/脊索动物分化之后且硬骨脊椎动物辐射之前。有人提出，在文昌鱼和有头类动物（脊椎动物 + 盲鳗）祖先分离之后，脊椎动物谱系中发生了两轮基因复制。在这些复制之前，导致脊椎动物旁系同源基因家族的基因在有头类动物祖先中必定是物理连锁的。在果蝇和秀丽隐杆线虫基因组中可以找到其中一些基因的连锁关系，这表明它们在三胚层后生动物祖先中是连锁的。
