title: The chicken polydactyly (Po) locus causes allelic imbalance and ectopic expression of Shh during limb development.
abstract: Point mutations in the intronic ZRS region of Lmbr1, a limb specific cis-regulatory element of Sonic hedgehog (Shh), are associated with polydactyly in humans, cats, and mice. We and others have recently mapped the dominant preaxial polydactyly (Po) locus in Silkie chickens to a single nucleotide polymorphism (SNP) in the ZRS region. Using polymorphisms in the chicken Shh sequence, we confirm that the ZRS region directly regulates Shh expression in the developing limb causing ectopic Shh expression in the anterior leg, prolonged Shh expression in the posterior limb, and allelic imbalance between wt and Slk Shh alleles in heterozygote limbs. Using Silkie legs, we have explored the consequences of increased Shh expression in the posterior leg on the patterning of the toes, and the induction of preaxial polydactyly.
authors.affiliation: Division of Genetics and Genomics, The Roslin Institute and Royal Dick School of Veterinary Studies, University of Edinburgh, Roslin, Midlothian, UK.
authors.forename: Ian C
authors.initials: IC
authors.lastname: Dunn
authors.forename: I Robert
authors.initials: IR
authors.lastname: Paton
authors.forename: Allyson K
authors.initials: AK
authors.lastname: Clelland
authors.forename: Sujith
authors.initials: S
authors.lastname: Sebastian
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Johnson
authors.forename: Lynn
authors.initials: L
authors.lastname: McTeir
authors.forename: Dawn
authors.initials: D
authors.lastname: Windsor
authors.forename: Adrian
authors.initials: A
authors.lastname: Sherman
authors.forename: Helen
authors.initials: H
authors.lastname: Sang
authors.forename: Dave W
authors.initials: DW
authors.lastname: Burt
authors.forename: Cheryll
authors.initials: C
authors.lastname: Tickle
authors.forename: Megan G
authors.initials: MG
authors.lastname: Davey
mesh_terms: D000818:Animals; D002415:Cats; D002642:Chick Embryo; D002645:Chickens; D005121:Extremities / Q000196:embryology*; D005838:Genotype; D053823:Hedgehog Proteins / Q000235:genetics / Q000378:metabolism*; D017403:In Situ Hybridization; D051379:Mice; D017689:Polydactyly; D012150:Polymorphism, Restriction Fragment Length / Q000235:genetics; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D040641:Quantitative Trait Loci / Q000235:genetics
chemical_list: D053823:Hedgehog Proteins