The Origins of Life: Old Problems, New Chemistries
The Origins of Life: Old Problems, New Chemistries
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DOI：
10.1002/anie.201204968
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发表时间：
2013-01-01
影响因子：
16.6
通讯作者：
Mann, Stephen
中科院分区：
文献类型：
--
作者：
Mann, Stephen
It is ironic that modern biology—considered by many to be the pre-eminent science of the 21st century—tells us everything we know about life as it exists today, but nothing substantial about its origin on the early Earth some 3.5–3.8 billion years ago.[1] Biology is underscored by two great principles: that all life is interconnected through a Darwinian landscape of random variation and selective retention, and that cellularity is the fundamental and universal organizational unit of life. We know much about the details of these principles and their molecular basis; in particular, how they depend on out-of-equilibrium energization, informational capacity, and matter/energy throughput,[2, 3] and how material embodiment is maintained throughout eons by processes of self-replication, metabolism and compartmentalization.[4] But a study of biology offers no illumination on the origin of life—on how life first emerged in a physical universe. If anything, it compounds this problem by showcasing an overarching commonality in which the phylogenetic histories of known organisms can be traced through the molecular archives of ribosomal RNA to a putative last universal common ancestor (LUCA) with most of the central biochemical machinery of extant cells still in place. Although the level of detail emanating from this molecular historicity is remarkable—for example, the recent unraveling of the origin and evolution of the ribosome [5]—there remains an intractable discontinuity at the base of the reconstructed tree of life, where all current knowledge of biology becomes effectively bottlenecked such that the origin of life appears impenetrable and mysterious. Metaphorically speaking, the tree of life appears rootless. We are therefore left with two momentous challenges: how did the transition from inanimate matter to the first forms of living matter occur on the early earth? And can a similar transition be realized ex novo in the laboratory? These are profound etiological questions that most biologists justifiably walk away from; should chemists do so too? Understandably, most chemists are resistant to undertaking research in this area for several reasons. To a cynic it may be that there is simply no critical level of funding. But there are more fundamental problems, principally to do with epistemology and methodology. Chemistry is viewed on the whole as an ahistorical science, unlike biology and earth sciences for example, and from this perspective there are strong objections to the study of the origin of life on the early Earth. This is compounded by the absence of statistically significant, reproducible and empirical data. Indeed, it is reasonable to question whether a systematic and meaningful investigation can ever be undertaken if no trace of life before the LUCA can be acquired. Thus, the irrevocable erasing of prebiotic signatures by Archean geochemistry, the fragmentary and rudimentary nature of models of the early Earth atmosphere and oceans, the sheer impossibility of reconstructing local chemical conditions, and the perceived weakness of the underlying theories are sufficient reasons to halt a concerted chemical approach to solving the origin of life. In a perfect world, many of these concerns might simply evaporate if we had a robust mathematical theory to describe the transition from inanimate to living matter.(In fact, there are many computational models [6, 7] and theories,[8–10] but none which provide an overarching description). Then the study of the origin of life would sit comfortably alongside mathematical theories of the origin of the universe. The latter are so sufficiently advanced that they drive high-cost, large-scale, multi-national research activities, such as the Large …
