"Thus, if Hox genes are responsible for determining the vertebral formula in all tetrapods ... complex when you look across the wider group of animals. Hox genes are still doing something in ...

A clear link between the arrangement of vertebrae in the spine and certain genes holds for mammals, but not for birds and amphibians Figure 1: A skeleton of a Steller’s sea eagle, of northeastern Asia ...

Nagoya, Japan - In the evolution of tetrapods, the position of the hindlimb has diversified along with the vertebral formula ... group also includes many other animals without four or any feet ...