(*) Somethying I found on the WWWeb suggests that a key genetic
change involves the expression of "Sonic Hedgehog": essential to
development of both fore and hind limbs, suppressed in the
hindquarters in modern Cetaceans.
Certainly. Shh is involved in all outgrowths of vertebrate body walls --
limbs, hair, feathers, scales, teeth, taste buds, everything.