[bioRxiv] Our biosphere exhibits remarkable diversity yet is constrained by universal organizational principles, including molecular homochirality.
Advances in synthetic biology have raised the possibility of engineering alternative life forms based on mirror-image biomolecules, prompting both technological interest and biosecurity concerns.
While current discussions of mirror life largely emphasize molecular feasibility and cellular function, its potential establishment in natural environments remains poorly understood.
Here, we develop a theoretical framework to assess the invasion potential of mirror organisms within existing ecosystems. Using population-level models that incorporate resource competition, metabolic constraints, and ecological network interactions, we show that mirror life might face severe limitations arising from both nutrient incompatibility and competitive exclusion by established biota.
In particular, the reliance on rare or achiral substrates and the asymmetry of interactions with natural organisms constrain growth and persistence across a broad range of ecological conditions. These results highlight the importance of ecological constraints in evaluating the risks and feasibility of synthetic life.
Ecological interactions between natural and mirror life. (a) Three classes of molecular resources are considered: standard chiral metabolites compatible with extant biochemistry (Cn), their mirror-chiral counterparts (Cm), and achiral compounds (A), which can in principle be accessed by both types of organisms. (b) Closed ecosystem. Two microbial populations are present: a resident community of natural organisms (N) and a mirror-life population (M). Both populations transform and recycle resources through metabolic processes and contribute to the production of shared and chiral compounds, with a fraction of flux channeled into achiral resources and the remainder into chiral pools. Interactions between N and M are indirect and mediated by resource availability, with no external inputs or losses. (c) Controlled open system (chemostat-like dynamics). Resources (A, Cn, Cm) are supplied through external fluxes, and both resources and populations are subject to dilution. Resource uptake and conversion are characterized by effective metabolic rates, while growth depends on resourcedependent feedbacks. In this regime, competition between natural and mirror populations is mediated by shared access to achiral compounds and by the transformation of resource pools under continuous flow conditions. (d) Generalized multispecies open system. Multiple resident populations (N) and a mirror variant of a resident (M) compete for externally supplied resources (A, Cn, Cm) under dilution. Primary interactions with resources are shown in black; all other interactions, including resource interconversions, are shown in grey. (e) Closed ecosystem with a natural predator. The system from (b) is extended by adding a predator population that targets the natural organisms. Interactions already present in the closed ecosystem are dimmed in grey. (f) Open system with an immune response. A mirror bacterial population grows in an open tissue environment and is subject to predation by macrophages. A vessel on top represents source for the arrival and removal of macrophages at defined rates. — bioRxiv.org
Ecological constraints to mirror life, bioRxiv.org
Astrobiology, Genomics, SynBio,
