Behavior of Chick Primordial Germ Cells Injected into the Blood Stream of Quail Embryos

The distribution and behavior of chick primordial germ cells (PGC) injected into quail embryos were examined. PGC from chick embryos at stages 13-14 were injected into the blood stream of quail embryos at stages 15-20. After one day, the quail embryos were examined histologically. The chick PGC in the quail embryos could be readily identified by the histochemical PAS technique, whereas quail PGC were never stained by PAS. When the chick PGC were injected into the quail embryos during stages 15-18, they appeared mostly in the gonadal region of the recipient quail embryos. A few PGC were found at extragonadal sites. When the chick PGC were injected into the quail embryos at stages 19-20, in which the PGC of the recipient quail embryos had finished their migration into the gonads, most of the donor chick PGC were found at ectopic sites, in the head, trunk and limbs. These results indicate that most of the chick PGC, injected at the earlier stages 15-18, migrated to the gonadal anlagen of the recipient, while following later injection (from stage 19), most of the chick PGC migrated to ectopic sites.