{
  "id": 5639000,
  "title": "Gene duplication shaped the origin and evolution of the vertebrate olfactory combinatorial code",
  "url": "https://urgent.news/2026/09/04/gene-duplication-shaped-the-origin-and-evolution-of-the-vertebrate",
  "topic": "science",
  "section": "Science",
  "published": "2026-09-04T00:00:00.000Z",
  "source": {
    "name": "bioRxiv",
    "slug": "biorxiv",
    "url": "https://www.biorxiv.org/content/10.64898/2026.08.31.747588v1?rss=1"
  },
  "original_language": "en",
  "account": "Animals detect their chemical environment through olfactory receptors, which are part of the class A GPCRs and constitute the largest gene family dedicated to a single function in animals. Each odorant molecule stimulates a unique combination of receptors, projects distinctively in the brain, and results in a distinct odor perception. The principles behind this coding are well-understood, and the evolution and regulation of these genes are areas of active research. However, the origins and evolution of this code have not been thoroughly explored. This study integrates phylogenetics, receptor-ligand interactions based on protein-chemical language models, ancestral sequence reconstruction, and analysis of chemical space. The findings indicate that odorants can be categorized into six clusters, each associated with a specific set of odor descriptors, implying that molecules processed by similar receptor combinations tend to have similar smells. The reconstructed ancestors suggest that the code's origin dates back to the first duplication of the gene family, occurring in the gnathostome ancestor during the class I/class II split. The initial duplicates then diverged asymmetrically into separate chemical spaces. One retained a third of the original ligands, while the other underwent extensive tuning and became specialized for carboxylic acids, a chemical class predominantly linked with class I receptors. Aromatics were retained and concentrated on the class II side. Crucially, the study concludes that this combinatorial coding did not originate from scratch; it emerged once, following the first duplication, and has persisted ever since.",
  "summary": "Animals read their chemical environment through olfactory receptors, which form part of the class A GPCRs and are the largest gene family devoted to a single function in animals. Each odorant molecule activates a different combination of receptors, projects distinctly in the brain, and so yields a distinct odour percept. The principles of this coding are well described, and the evolution and…",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}