Golding G B, Gupta R S
Department of Biology, McMaster University, Hamilton, Ontario, Canada.
Mol Biol Evol. 1995 Jan;12(1):1-6. doi: 10.1093/oxfordjournals.molbev.a040178.
The phylogenetic position of the archaebacteria and the place of eukaryotes in the history of life remain a question of debate. Recent studies based on some protein-sequence data have obtained unusual phylogenies for these organisms. We therefore collected the protein sequences that were available with representatives from each of the major forms of life: the gram-negative bacteria, gram-positive bacteria, archaebacteria, and eukaryotes. Monophyletic, unrooted phylogenies based on these sequence data show that seven of 24 proteins yield a significant gram-positive-archaebacteria clade/gram-negative-eukaryotic clade. The phylogenies for these seven proteins cannot be explained by the traditional three-way split of the eukaryotes, archaebacteria, and eubacteria. Nine of the 24 proteins yield the traditional gram-positive-gram-negative clade/archaebacteria-eukaryotic clade. The remaining eight proteins give phylogenies that cannot be statistically distinguished. These results support the hypothesis of a chimeric origin for the eukaryotic cell nucleus formed from the fusion of an archaebacteria and a gram-negative bacteria.
古细菌的系统发育位置以及真核生物在生命史上的地位仍然是一个有争议的问题。最近基于一些蛋白质序列数据的研究为这些生物获得了不同寻常的系统发育树。因此，我们收集了来自生命主要形式（革兰氏阴性菌、革兰氏阳性菌、古细菌和真核生物）各代表的可用蛋白质序列。基于这些序列数据构建的单系、无根系统发育树表明，24种蛋白质中有7种产生了显著的革兰氏阳性菌 - 古细菌分支/革兰氏阴性菌 - 真核生物分支。这7种蛋白质的系统发育树无法用真核生物、古细菌和真细菌传统的三分法来解释。24种蛋白质中有9种产生了传统的革兰氏阳性菌 - 革兰氏阴性菌分支/古细菌 - 真核生物分支。其余8种蛋白质给出的系统发育树在统计学上无法区分。这些结果支持了真核细胞核由古细菌和革兰氏阴性菌融合形成的嵌合起源假说。
