Outsourcing of energetically costly amino acids at the origin of animals.

ABSTRACT: Animals are generally capable of synthesizing eleven amino acids, while the remaining nine-often referred to as essential-must be acquired through diet. This metabolic trait profoundly shapes animal ecology and evolutionary trajectories, and recent phylogenomic studies indicate that it arose from gene losses at the root of the animal tree. However, it remains unclear which selective forces, if any, directed this far-reaching metabolic simplification. Here, we show that essential amino acids are energetically far more expensive to synthesize than non-essential ones, particularly under high respiratory conditions-a hallmark of the animal lifestyle. Using a probabilistic selection test, we find support for the hypothesis that energy-related selection, counterbalanced by pleiotropic effects, f

SUBMITTER: Kasalo N 

PROVIDER: S-EPMC12923814 | biostudies-literature | 2026 Jan

REPOSITORIES: biostudies-literature