Those discs that form the spine originate in embryonic blueprint segments called somites. As the embryo body elongates in all vertebrate species, it is cut into somites by a "biological clock knife." ...

Adding just the right mixture of signaling molecules — proteins involved in development — to human stem cells can coax them to resemble somites, which are groups of cells that give rise to skeletal ...

At an early stage in vertebrates' embryonic development somites form: these are primitive segments from which the spine, ribs, back muscles, cartilage, tendons and part of the skin develop.

Those discs that form the spine originate in embryonic blueprint segments called somites. As the embryo body elongates in all vertebrate species, it is cut into somites by a "biological clock knife." ...