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
Featherless bird-riddle Featherless bird-riddle The Featherless bird-riddle is an international riddle type about a snowflake. In the nineteenth century, it attracted considerable scholarly attention because it was seen as a possible reflex of ancient Germanic riddling, arising from magical incantations. But although the language of the riddle is reminiscent of European charms, later work, particularly by Antti Aarne, showed that it occurred widely throughout Europe─particularly central Europe─and that it is therefore an international riddle type. Archer Taylor concluded that 'the equating of a snowflake to a bird and the sun to a maiden without hands is an elementary idea that cannot yield