Glansdorff N
Microbiology, Free University of Brussels (VUB), Flanders Interuniversity Institute and J.-M. Wiame Microbiological Research Institute, Brussels B-1070, Belgium.
Mol Microbiol. 2000 Oct;38(2):177-85. doi: 10.1046/j.1365-2958.2000.02126.x.
An organismal tree rooted in the bacterial branch and derived from a hyperthermophilic last common ancestor (LCA) is still widely assumed to represent the path followed by evolution from the most primeval cells to the three domains recognized among contemporary organisms: Bacteria, Archaea and Eucarya. In the past few years, however, more and more discrepancies between this pattern and individual protein trees have been brought to light. There has been an overall tendency to attribute these incongruities to widespread lateral gene transfer. However, recent developments, a reappraisal of earlier evidence and considerations of our own lead us to a quite different view. It would appear (i) that the role of lateral gene transfer was overemphasized in recent discussions of molecular phylogenies; (ii) that the LCA was probably a non-thermophilic protoeukaryote from which both Archaea and Bacteria emerged by reductive evolution but not as sister groups, in keeping with a current evolutionary scheme for the biosynthesis of membrane lipids; and (iii) that thermophilic Archaea may have been the first branch to diverge from the ancestral line.
一种根植于细菌分支且源自嗜热的最后共同祖先（LCA）的生物树，至今仍被广泛认为代表了从最原始细胞到当代生物中所认可的三个域（细菌、古菌和真核生物）的进化路径。然而，在过去几年里，这种模式与单个蛋白质树之间越来越多的差异被揭示出来。总体趋势是将这些不一致归因于广泛的横向基因转移。然而，近期的进展、对早期证据的重新评估以及我们自己的思考，使我们得出了截然不同的观点。似乎（i）在最近关于分子系统发育的讨论中，横向基因转移的作用被过度强调了；（ii）LCA可能是一种非嗜热的原始真核生物，古菌和细菌都是从它通过简化进化而来，但并非作为姐妹群，这与当前膜脂生物合成的进化方案一致；（iii）嗜热古菌可能是从祖先谱系中最早分化出来的分支。
