{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"d7d45e33fe8a57b0245fd7a8fc8b6e73eccbd74cf6c0559d11e5176176c45a91","created":"2026-10-03T07:17:57Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"9b6689ad4f06eff6b589fd3cd8b397d065a2a8ce40e874dd212a2316567e216d","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":[],"external_id":"bio.cellular-sensing.positional-optimality","kind":"well-posed","literature_status":"partially-resolved","n":"1","parents":[],"plain":"In the fruit-fly embryo, a few genes switched on in graded patterns tell each cell where it is with about 1 percent precision. One hypothesis is that these networks are tuned to carry the most positional information possible given their noise.","posed_since":"","precise":"For the Drosophila gap-gene network (hunchback, Kruppel, knirps, giant) driven by maternal gradients, maximize the mutual information $I(x; g)$ between position $x$ and expression vector $g$ at a fixed budget of molecules and the measured noise, and test whether the optimal network, with no parameters fitted to gap-gene profiles, predicts the measured profiles, the positional error of about $0.01\\,L$ ($L$ = egg length), and mutant phenotypes. Answer: yes or no for wild type and for mutants or other species.","problem_ref":null,"references":"","settled_by":"Parameter-free predictions of the optimized network compared with measured expression profiles in mutants and in other fly species.","status_note":"An optimization-based derivation (Sokolowski, Gregor, Bialek, Tkacik; arXiv 2302.05680, 2023) reproduced key features of the wild-type network; out-of-sample tests remain open.","title":"Are embryonic gene networks optimal encoders of position?","topic_ref":"162aec31a0a35d10d7205c0113216cb9f810fe4d327304e36437346a256186d4"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"bdf37cc8b43411156013bd9143e7cf56401a2d29dd9169baf1faef7347064280","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"05ecfd1fc033782963613e5025b2f2fde0cf5e41ca50a459da486248950b4f0c","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"-F_AzRxhF676LX_SxwyeDc1lJ1QS0SF7BOdi6UhOfsk83df1IikD7hOXT4q11d8UJ5H6-3L1iQOv-Jj__ki4Ag"},"schema":"pubphys.envelope/1"},"record_hash":"bdf37cc8b43411156013bd9143e7cf56401a2d29dd9169baf1faef7347064280","leaf_index":737}