Silkie the "SHH" gene, called the ZPA Regulatory Sequence (ZRS). This causes ectopic "SHH" expression in the anterior of the developing limb bud, leading to increased tissue growth and digits. While the feet of the Silkie display polydactyly, the wings have the standard tridactyly (three digit) arrangement. The Japanese Silkie initially develops additional digits in the wing as an embryo, but these are lost prior to hatching. The genetic cause behind Silkie polydactyly differs from those that cause polydactyly in the Dorking chicken breed, which is due to ectopic "FGF4" expression in the AER, with ectopic "SHH" a secondary effect. The
The Bird 'Grip' ever after. While the hero in these stories is normally aided by a talking animal, for it to be a ghost is unusual. This is the grateful dead, a common folklore motif, found also in "Fair Brow". The Bird 'Grip' The Bird 'Grip' is a Swedish fairy tale. Andrew Lang included it "The Pink Fairy Book". It is Aarne-Thompson type 550, the quest for the golden bird/firebird; other tales of this type include "The Golden Bird", "The Greek Princess and the Young Gardener", "How Ian Direach got the Blue Falcon", "The Nunda, Eater of People", and "Tsarevitch Ivan, the Fire