Origin of the avian glycogen body: I. Effects of tail bud removal in the chick embryo.

The tail bud was removed from chick embryos at stage 16-17 in a first study directed to learn of the origin of the glycogen body in the lumbosacral spinal cord of birds. Results of tail bud removal and chorio-allantoic grafting of caudal portions of the embryo containing the tail bud or the neural tube suggest that the glycogen body does not arise from the tail bud, but from the preexisting neural tube craniad or anterior to the tail bud. The stem cells of the glycogen body are most likely among those components of the anterior portion of the lumbosacral neural tube derived from primary neurulation.