Advances in origins of life research and prebiotic chemistry suggest that life as we know it may have emerged from an earlier RNA World. However, it has been difficult to reconcile the conditions used in laboratory experiments with real‐world geochemical environments that may have existed on the early Earth and hosted the origin(s) of life. This challenge is due to geologic resurfacing and recycling that have erased the overwhelming majority of the Earth's prebiotic history. We therefore propose that Mars, a planet frozen in time, comprised of many surfaces that have remained relatively unchanged since their formation > 4 Gya, is the best alternative to search for environments consistent with geochemical requirements imposed by the RNA world. In this study, we synthesize in situ and orbital observations of Mars and modeling of its early atmosphere into solutions containing a range of pHs and concentrations of prebiotically relevant metals (Fe²⁺, Mg²⁺, and Mn²⁺) spanning various candidate aqueous environments. We then experimentally determine RNA degradation kinetics due to metal‐catalyzed hydrolysis (cleavage) and evaluate whether early Mars could have been permissive toward the accumulation of long‐lived RNA polymers. Our results indicate that a Mg²⁺‐rich basalt sourcing metals to a slightly acidic (pH 5.4) environment mediates the slowest rates of RNA cleavage, though geologic evidence and basalt weathering models suggest aquifers on Mars would be near neutral (pH ~ 7). Moreover, the early onset of oxidizing conditions on Mars has major consequences regarding the availability of oxygen‐sensitive metals (i.e., Fe²⁺ and Mn²⁺) due to increased RNA degradation rates and precipitation. Overall, (a) low pH decreases RNA cleavage at high metal concentrations; (b) acidic to neutral pH environments with Fe²⁺ or Mn²⁺ cleave more RNA than Mg²⁺; and (c) alkaline environments with Mg²⁺ dramatically cleaves more RNA while precipitates were observed for Fe²⁺ and Mn²⁺.

中文翻译：

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寻找火星上的RNA世界

生命研究和益生元化学的起源方面的进展表明，我们所知道的生命可能起源于更早的RNA世界。但是，很难将实验室实验中使用的条件与地球早期可能已经存在并具有生命起源的现实地球化学环境进行调和。这项挑战是由于地质重塑和循环利用已经抹去了地球绝大多数益生元历史。因此，我们建议火星是一颗及时冻结的行星，由许多表面组成，这些表面自形成以来就保持相对不变[4 Gya]，是寻找与RNA世界所施加的地球化学要求相符的环境的最佳选择。在这项研究中，²⁺，Mg ²⁺和Mn ²⁺）跨越各种候选水环境。然后，我们通过实验确定由于金属催化的水解（裂解）而引起的RNA降解动力学，并评估火星早期是否允许长寿命RNA聚合物的积累。我们的结果表明，尽管地质证据和玄武岩风化模型表明，火星上的含水层接近中性（pH约为7），但富含Mg ^2+的玄武岩将金属采购到微酸性（pH 5.4）环境中时，RNA裂解的速率最慢。 。此外，火星上氧化条件的早期发作对氧敏感金属（如Fe ²⁺和Mn ²⁺）是由于增加了RNA降解速率和沉淀。总的来说，（a）低pH降低了高金属浓度下的RNA裂解；（b）在酸性至中性pH的环境中，Fe ²⁺或Mn ^2+的裂解RNA大于Mg ²⁺；（c）含Mg ^2+的碱性环境会显着裂解更多的RNA，同时观察到Fe ²⁺和Mn ^2+的沉淀。