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
What Bird is That? friends, together with the succinct but compendious descriptive information, will place within easy reach of the bird lover, a most valuable "vade mecum" of bird and bush lore for out of doors as well as a thing of beauty for the library." Cayley’s aim in creating this work was to make available a book that would encourage and help people to learn about and appreciate Australia’s remarkable and unique bird life. He saw and responded to a need for a simple book that was accessible to the non-specialist birdwatcher. Each species was illustrated in colour and the birds were organised