Sonic hedgehog protein
protein-coding gene in the species Homo sapiens
Sonic hedgehog protein (SHH) is a major signaling molecule of embryonic development in planulozoan animals, encoded by the SHH gene.
This signaling molecule is key in regulating embryonic morphogenesis in complex animals. SHH controls organogenesis and the organization of the central nervous system, limbs, digits and many other parts of the body. Sonic hedgehog is a morphogen that patterns the developing embryo using a concentration gradient characterized by the French flag model. This model has a non-uniform distribution of SHH molecules which governs different cell fates according to concentration. Mutations in this gene can cause holoprosencephaly, a failure of splitting in the cerebral hemispheres, as demonstrated in an experiment using SHH knock-out mice in which the forebrain midline failed to develop and instead only a single fused telencephalic vesicle resulted.
Sonic hedgehog still plays a role in differentiation, proliferation, and maintenance of adult tissues. Abnormal activation of SHH signaling in adult tissues has been implicated in various types of cancers including breast, skin, brain, liver, gallbladder and many more.
Discovery and naming
The hedgehog gene (hh) was first identified in the fruit fly Drosophila melanogaster in the classic Heidelberg screens of Christiane Nüsslein-Volhard and Eric Wieschaus, as published in 1980. These screens, which led to the researchers winning a Nobel Prize in 1995 along with developmental geneticist Edward B. Lewis, identified genes that control the segmentation pattern of the Drosophila embryos.
Begin with the source’s own compact description: “Sonic hedgehog protein” is protein-coding gene in the species Homo sapiens. The dossier treats that line as a proposition to test through Sonic, hedgehog and protein, not as a finished interpretation.
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The date and method of observation matter as much as the stated conclusion, especially where classification or consensus has changed. The source revision retrieved here is dated Aug 13, 2026. The linked authority identifier is Q14860072. None of the 0 selected statements returned an explicit reference. The first chronological checks are 1980 and 1995.
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This entry incorporates text from “Sonic hedgehog protein” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.