Doolittle W F, Brown J R
Canadian Institute for Advanced Research, Halifax, NS.
Proc Natl Acad Sci U S A. 1994 Jul 19;91(15):6721-8. doi: 10.1073/pnas.91.15.6721.
Early cellular evolution differed in both mode and tempo from the contemporary process. If modern lineages first began to diverge when the phenotype-genotype coupling was still poorly articulated, then we might be able to learn something about the evolution of that coupling through comparing the molecular biologies of living organisms. The issue is whether the last common ancestor of all life, the cenancestor, was a primitive entity, a progenote, with a more rudimentary genetic information-transfer system. Thinking on this issue is still unsettled. Much depends on the placement of the root of the universal tree and on whether or not lateral transfer renders such rooting meaningless.
早期细胞进化在方式和节奏上都与当代过程有所不同。如果现代谱系在表型-基因型耦合仍未充分阐明时就首次开始分化，那么我们或许能够通过比较生物的分子生物学来了解这种耦合的进化情况。问题在于，所有生命的最后共同祖先，即共同祖先，是否是一个具有更原始遗传信息传递系统的原始实体，即原核生物。关于这个问题的思考仍未确定。很大程度上取决于通用树根部的位置，以及横向转移是否会使这种生根变得毫无意义。
