A comparative study of modern proteins identifies 40 fragments that may represent the observable remnants of a primordial RNA-peptide world.

Minimal changes allow an ancestral, unfolded peptide to adopt a known fold by repetition, illuminating a possible path for the emergence of folded proteins at the origin of life.

Evolutionary reconstruction of the ecdysis pathway shows that its major elements are present in the majority of metazoans, providing evidence that they originated much earlier than currently assumed.

Analysisof P-loop NTPases and Rossmans, the most ancient and diverse enzyme lineages, suggests their divergence from one ancestral polypeptide.

Analysis of the endogenous function of deeply conserved neuropeptides in sea anemones sheds light on a primitive role of nervous systems in modulating developmental timing.

mille-pattes micropeptides have conserved function in insect embryonic patterning together with transcription factor Shaven-baby and ubiquitin ligase Ubr3, except in flies wherein restoring broad embryonic Svb expression restores patterning potency.

Ancient hepatitis B virus (HBV) genomes were reconstructed from up to 7000-year-old Stone Age human skeletons, suggesting a long-time complex co-evolution with human populations.

Behavioral assays using Caenorhabditis elegans show that a learned pathogen avoidance following intestinal distention requires specific chemosensory neurons and TRPM channels in the intestine and excretory cell.

A chemically unstable ostrich eggshell peptide survives for at least 3.8 million years at the equator, stabilized by strong mineral interactions.

A small brain-derived lipid prevents bristle worms from entering maturation and death, challenging current views of hormone evolution and pesticide specificity.