Earth and Planets Laboratory, Carnegie Institution for Science, Washington, DC 20015, USA.
Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, IN 46556, USA.
J R Soc Interface. 2024 Feb;21(211):20230632. doi: 10.1098/rsif.2023.0632. Epub 2024 Feb 21.
Molecular assembly indices, which measure the number of unique sequential steps theoretically required to construct a three-dimensional molecule from its constituent atomic bonds, have been proposed as potential biosignatures. A central hypothesis of assembly theory is that any molecule with an assembly index ≥15 found in significant local concentrations represents an unambiguous sign of life. We show that abiotic molecule-like heteropolyanions, which assemble in aqueous solution as precursors to some mineral crystals, range in molecular assembly indices from 2 for HCO or Si(OH) groups to as large as 21 for the most complex known molecule-like subunits in the rare minerals ewingite and ilmajokite. Therefore, values of molecular assembly indices ≥15 do not represent unambiguous biosignatures.
分子组装指数，用于衡量从组成原子键构建三维分子所需的独特连续步骤的数量，被提议作为潜在的生物特征。组装理论的一个中心假设是，在显著的局部浓度下发现的任何具有组装指数≥15 的分子，都代表生命的明确标志。我们表明，在水溶液中组装为某些矿物晶体前体的非生物分子样杂多阴离子，其分子组装指数范围从 HCO 或 Si(OH) 基团的 2 到最复杂的已知分子样亚基在稀有矿物 ewingite 和 ilmajokite 中的 21。因此，组装指数≥15 的值并不代表明确的生物特征。
