Spatial patterning and selection: How the environment shapes molecular complexity
4 affiliations
- 1Département de physique, Université de Montréal , Montréal, QC H2V 0B3 ,
- 2Biodesign Institute, Arizona State University , Tempe, AZ 85281 ,
- 3Santa Fe Institute , Santa Fe, NM 87501 ,
- 4School of Complex Adaptive Systems, Arizona State University , Tempe, AZ 85281 ,
Abstract
Assembly theory predicts that a distinguishing signature of life is its ability to produce complex molecules in abundance, opening new possibilities for life detection. Experimental validation of this approach has so far relied on abiotic controls like meteoritic material, or simple, well-mixed chemical systems. However, decades of research in self-organization have shown that spatial patterning can foster dynamical complexity. This raises the possibility that systems with spatial patterns might promote abiotic formation of molecules with higher-than-expected assembly indices—a measure defined within assembly theory to assess structural complexity—potentially leading to false positives in life detection approaches based on this framework. To probe this possibility, we compare how assembly indices in a simplified in silico chemistry scale relative to those in molecular space, and then ask how spatial organization shapes their distribution in our model. Our findings reveal that transport factors, such as diffusion, significantly affect the distribution of chemical species within a system. Additionally, spatial topology markedly shapes the distribution of assembly indices: while it does not enable arbitrary complexity, ordered lattices in particular can shift the assembly indices of abiotic chemistry upward. Moreover, we demonstrate that diffusion can impede the formation and detectable upper limit of these high assembly index molecules, bearing important implications for life detection experiments and astrobiological missions.
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BibTeX
@article{champagneruel2026spatial,
title = {{Spatial patterning and selection: How the environment shapes molecular complexity}},
author = {Alexandre Champagne-Ruel and Christopher P Kempes and Cole Mathis},
journal = {PNAS Nexus},
year = {2026},
month = oct,
doi = {10.1093/pnasnexus/pgag304},
url = {https://academic.oup.com/pnasnexus/article/doi/10.1093/pnasnexus/pgag304/8865179},
note = {CC BY-NC 4.0},
}
RIS
TY - JOUR
TI - Spatial patterning and selection: How the environment shapes molecular complexity
AU - Alexandre Champagne-Ruel
AU - Christopher P Kempes
AU - Cole Mathis
PY - 2026
DA - 2026/10/06
JO - PNAS Nexus
DO - 10.1093/pnasnexus/pgag304
UR - https://academic.oup.com/pnasnexus/article/doi/10.1093/pnasnexus/pgag304/8865179
AB - Assembly theory predicts that a distinguishing signature of life is its ability to produce complex molecules in abundance, opening new possibilities for life detection. Experimental validation of this approach has so far relied on abiotic controls like meteoritic material, or simple, well-mixed chemical systems. However, decades of research in self-organization have shown that spatial patterning can foster dynamical complexity. This raises the possibility that systems with spatial patterns might promote abiotic formation of molecules with higher-than-expected assembly indices—a measure defined within assembly theory to assess structural complexity—potentially leading to false positives in life detection approaches based on this framework. To probe this possibility, we compare how assembly indices in a simplified in silico chemistry scale relative to those in molecular space, and then ask how spatial organization shapes their distribution in our model. Our findings reveal that transport factors, such as diffusion, significantly affect the distribution of chemical species within a system. Additionally, spatial topology markedly shapes the distribution of assembly indices: while it does not enable arbitrary complexity, ordered lattices in particular can shift the assembly indices of abiotic chemistry upward. Moreover, we demonstrate that diffusion can impede the formation and detectable upper limit of these high assembly index molecules, bearing important implications for life detection experiments and astrobiological missions.
SN - 2752-6542
ER -