一项发表在《Science Advances》期刊上的新研究提出了一个激进的观点，认为地球上的生命可能经历了两次独立的起源事件。[1] 研究团队通过分析核心代谢酶的蛋白质结构发现，细菌和古菌这两大生命系统可能各自独立地演化出了代谢能力，从非生命物质升级为生命体，而非源于同一共同祖先。[1]
研究表明，细菌和古菌的代谢酶在进化上并不保守，两者独立进化出了结构不同的酶来催化相同的代谢反应。[1] 德国杜塞尔多夫海因里希·海涅大学的研究人员指出，最后通用共同祖先（LUCA）只拥有约一半代谢反应所需的酶，其余反应则由环境中的金属催化。[1] 研究人员威廉·马丁表示："我们看到的是一个遗传密码的起源，但却是两个生命的起源。"[1]
A new study published in Science Advances proposes that life on Earth may have originated independently on two separate occasions. [1] Rather than descending from a single common ancestor, bacteria and archaea—the two major branches of cellular life—appear to have evolved their metabolic capabilities independently, each transitioning from non-living matter to living systems through distinct evolutionary pathways. [1]
Researchers led by William Martin and colleagues at Heinrich Heine University Düsseldorf analyzed the protein structures of core metabolic enzymes across these two domains and discovered that they independently evolved structurally different enzymes to catalyze identical metabolic reactions. [1] According to Martin, "we are looking at one origin of the genetic code, but two origins of life." [1] The study indicates that LUCA (the Last Universal Common Ancestor) possessed enzymes for only approximately half of essential metabolic reactions. [1] The remaining reactions were likely catalyzed by metals present in the environment rather than by proteins, with phosphate and palladium capable of substituting for ATP and enzymes in performing metabolic phosphorylation. [1]