內(nèi)共生（不同生命形式融合起來創(chuàng)造一個(gè)新的,、更復(fù)雜的整體）被認(rèn)為在復(fù)雜細(xì)胞的演化中具有重要作用。細(xì)胞的不同部分——細(xì)胞核,、線粒體等——是曾經(jīng)獨(dú)立的生物體的殘跡,。但內(nèi)共生是否在較簡單的生物如細(xì)菌的演化中也曾扮演一個(gè)角色？這個(gè)問題通常沒有被人們所考慮,，因?yàn)檫@些生物沒有分成不同部分的內(nèi)部結(jié)構(gòu),。然而，很多成功的和重要的細(xì)菌都有雙層細(xì)胞膜,，而且在本期Nature上的一篇“假說”文章中,，James Lake提出，這是兩種不同細(xì)菌細(xì)胞類型之間的融合遺留下來的,，這兩種細(xì)菌細(xì)胞類型分別是梭菌和放射菌,。（生物谷Bioon.com）
生物谷推薦原始出處：
Nature, 967-971 (20 August 2009) | doi:10.1038/nature08183
Evidence for an early prokaryotic endosymbiosis
James A. Lake
Endosymbioses have dramatically altered eukaryotic life, but are thought to have negligibly affected prokaryotic evolution. Here, by analysing the flows of protein families, I present evidence that the double-membrane, Gram-negative prokaryotes were formed as the result of a symbiosis between an ancient actinobacterium and an ancient clostridium.
