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
Blue Bird Mini Bird Blue Bird Mini Bird The Blue Bird Mini Bird was a Type B school bus built by Blue Bird Corporation, introduced in 1977. It was dropped in the early 2000s as market tastes shifted away from Type B school buses. In 1977, Blue Bird introduced the Mini Bird as a Type B school bus. It was designed with a maximum capacity of 38 students, higher than the Type A cutaway vans of the time. In the manner of larger Type C and Type D buses, the Mini Bird was designed with a 96" (243 cm) wide body and 77" (195