Brunk Clifford F, Marshall Charles R
Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, CA 90095-1606, USA.
Department of Integrative Biology, Museum of Paleontology, University of California, Berkeley, CA 94720-4780, USA.
Life (Basel). 2021 Jul 14;11(7):690. doi: 10.3390/life11070690.
While most advances in the study of the origin of life on Earth (OoLoE) are piecemeal, tested against the laws of chemistry and physics, ultimately the goal is to develop an overall scenario for life's origin(s). However, the dimensionality of non-equilibrium chemical systems, from the range of possible boundary conditions and chemical interactions, renders the application of chemical and physical laws difficult. Here we outline a set of simple criteria for evaluating OoLoE scenarios. These include the need for containment, steady energy and material flows, and structured spatial heterogeneity from the outset. The Principle of Continuity, the fact that all life today was derived from first life, suggests favoring scenarios with fewer non-analog (not seen in life today) to analog (seen in life today) transitions in the inferred first biochemical pathways. Top-down data also indicate that a complex metabolism predated ribozymes and enzymes, and that full cellular autonomy and motility occurred post-LUCA. Using these criteria, we find the alkaline hydrothermal vent microchamber complex scenario with a late evolving exploitation of the natural occurring pH (or Na gradient) by ATP synthase the most compelling. However, there are as yet so many unknowns, we also advocate for the continued development of as many plausible scenarios as possible.
虽然地球生命起源(OoLoE)研究的大多数进展都是零散的,并根据化学和物理定律进行了检验,但最终目标是构建一个关于生命起源的整体设想。然而,非平衡化学系统的维度,从可能的边界条件和化学相互作用范围来看,使得化学和物理定律的应用变得困难。在此,我们概述了一套评估地球生命起源设想的简单标准。这些标准包括从一开始就需要有隔离、稳定的能量和物质流动以及结构化的空间异质性。连续性原则,即当今所有生命都源自最初的生命,这表明在推断的第一条生化途径中,倾向于选择非类似物(当今生命中未出现)到类似物(当今生命中出现)转变较少的设想。自上而下的数据还表明,复杂的新陈代谢早于核酶和酶出现,并且完全的细胞自主性和运动性在最后的共同祖先(LUCA)之后才出现。使用这些标准,我们发现碱性热液喷口微室复合体设想最具说服力,该设想中ATP合酶对自然存在的pH(或钠梯度)的利用是后期演化形成的。然而,目前仍有许多未知因素,我们也主张尽可能多地持续发展各种合理的设想。