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
Big Bird to the cassowary; he replied, "I'm more of a condor." On the January 23, 1976 episode of "Hollywood Squares", Big Bird was asked what kind of bird he is and said he was a lark, causing host Peter Marshall to crack up. In the film "Don't Eat the Pictures", Osiris calls Big Bird an ibis. Big Bird appeared in a series 11 episode of "Mister Rogers' Neighborhood", in which he declares he is a "golden condor". Zoologist Mike Dickison suggested in his popular Pechakucha talk that Big Bird represents a unique species that evolved from the whooping crane. Big Bird