{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"c77430b65b9e369283d429834aa06791169e98dd8aee375093838be063231745","created":"2026-10-03T07:17:57Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"b14da75a25ea1b626c68f775f0522598c124bf158484a714a7ffebea8c0a9bb6","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"mechanism","assisted_by":[],"external_id":"bio.origin-of-life.homochirality-origin","kind":"phenomenon","literature_status":"contested","n":"1","parents":[],"plain":"Many biological molecules come in mirror-image forms, yet life uses only left-handed amino acids and right-handed sugars. Whether this choice was set by a physical bias or by chance, and how it was amplified to purity, is unknown.","posed_since":"","precise":"Identify the symmetry-breaking event (a deterministic bias such as weak-interaction parity violation, circularly polarized light, or spin-polarized electrons from magnetic minerals; or spontaneous symmetry breaking) and the amplification mechanism (autocatalysis, crystallization, polymerization selectivity) that took a near-racemic prebiotic pool to enantiomeric excess $\\mathrm{ee} > 0.99$ in nucleotides and amino acids. Answer: a demonstrated, prebiotically plausible pathway.","problem_ref":null,"references":"","settled_by":"A laboratory sequence under plausible early-Earth conditions that produces enantiopure nucleotide and amino-acid building blocks from racemic or near-racemic feedstocks.","status_note":"Since 2023, spin-selective crystallization of an RNA precursor on magnetite surfaces has been proposed as a route (arXiv 2303.01394); its sufficiency and geological plausibility remain under discussion, to this survey's knowledge.","title":"How life came to use only one molecular handedness","topic_ref":"819c3cf4ef1ce5d66c72a382f1081518f28c7f8a56681c740fe7338f60746ab9"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"c9f8615966d6babc3a91fe7b5dabb8ff900ccc227835467260320f6f068052fc","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"4226d625fa26d3c75eaa22855d9ccc2c277f99359006d02e8f8f398a32f30102","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"SZNan32AdP2MgEHkXbcTRnDnTgdB9pv-1oTJ5aACeLqLu6GsllmpvKG_URjHf0XfObf75iGROXzWMev7FnZoAQ"},"schema":"pubphys.envelope/1"},"record_hash":"c9f8615966d6babc3a91fe7b5dabb8ff900ccc227835467260320f6f068052fc","leaf_index":817}