From life history to proteome via mutagenesis: an ecological footprint in genome evolution

Abstract

Species differ in longevity, physiology, and social organization, and these properties expose them to distinct endogenous and environmental mutagens. Mutational spectra generated by these processes can shape downstream molecular evolution, influencing synonymous nucleotide composition, codon usage, and even amino acid composition. Tracing this signal from life history to proteome through mutagenesis could reveal how mutational pressure interacts with the fitness landscape, including the direction of molecular change and the extent to which proteins remain functional while following mutational biases. Here, building on the recently identified age-associated mitochondrial A>G mutational signature in mammals, we test the universality of this signature and its downstream effects on genome and proteome evolution by comparing long-lived termites with short-lived non-termite cockroaches. We find that termite mtDNA exhibits a stronger A>G mutational signature than that of non-termite cockroaches, accompanied by coordinated shifts in synonymous nucleotide composition, codon usage, and amino acid composition. Our results show that ecological and life-history-associated mutational pressures can be transmitted through a hierarchy from mutational spectra to nucleotide composition and ultimately to proteome evolution. Mitochondrial genomes may therefore function not only as records of ancestry but also as molecular archives of the biological conditions under which species evolve.