Energy-harnessing problem solving of primordial life: Modeling the emergence of catalytic host-nested parasite life cycles

All life forms on earth ultimately descended from a primordial population dubbed the last universal common ancestor or LUCA via Darwinian evolution. Extant living systems share two salient functional features, a metabolism extracting and transforming energy required for survival, and an evolvable, informational polymer-the genome-conferring heredity. Genome replication invariably generates essential and ubiquitous genetic parasites. Here we model the energetic, replicative conditions of LUCA-like organisms and their parasites, as well as adaptive problem solving of host-parasite pairs. We show using an adapted Lotka-Volterra frame-work that three host-parasite pairs-individually a unit of a host and a parasite that is itself parasitized, therefore a nested parasite pair-are sufficient for robust and stable homeostasis, forming a life cycle. This nested parasitism model includes competition and habitat restriction. Its catalytic life cycle efficiently captures, channels and transforms energy, enabling dynamic host survival and adaptation. We propose a Malthusian fitness model for a quasispecies evolving through a host-nested parasite life cycle with two core features, rapid replacement of degenerate parasites and increasing evolutionary stability of host-nested parasite units from one to three pairs.

Automated summary

All life forms on earth can be traced back to a common ancestor called LUCA through Darwinian evolution. These life forms share two important features - a metabolism for extracting and converting energy, and a genetic system for heredity. However, genome replication often leads to the emergence of genetic parasites. In this study, we propose a model that simulates the energetic and replicative conditions of LUCA-like organisms and their parasites, and investigate the problem-solving abilities of host-parasite pairs. Our findings suggest that a nested parasitism model involving three host-parasite pairs can achieve robust and stable homeostasis, forming a complete life cycle. This model, which includes competition and habitat restriction, efficiently captures, channels, and transforms energy, enabling dynamic host survival and adaptation.