PRODUCTION OF GERMLINE CHIMERIC CHICKENS, WITH HIGH TRANSMISSION RATEOF DONOR-DERIVED GAMETES, PRODUCED BY TRANSFER OF PRIMORDIAL GERM-CELLS

Germline chimeric chickens were produced by transfer of primordial ger m cells from White Leghorn to Barred Plymouth Rock, and vice versa. Bl ood was collected from stage 13-15 embryos and primordial germ cells w ere concentrated by Ficoll density gradient centrifugation. Approximat ely 200 primordial germ cells were injected into the bloodstream throu gh the dorsal aorta of stage 14-15 recipient embryos from which blood had been drawn via the dorsal aorta prior to the injection. Intact emb ryos were also prepared as recipients for White Leghorns only. The man ipulated embryos were cultured in recipient eggshells until hatching. Germline chimerism of the chickens reaching maturity was examined by m ating them with Barred Plymouth Rocks and donor-derived offspring were identified based on their feather color. The efficiency of production of germline chimeras was 95% (19/20). When primordial germ cells were transferred from White Leghorn to Barred Plymouth Rock, the average f requency of donor-derived offspring was 81% for three male chimeras (9 6% for one female chimera), and it was similar to 3.5 times higher for transfer in the opposite direction (23% for 6 male chimeras). Removin g blood from recipient embryos prior to primordial germ cell injection enhanced the frequency of donor-derived offspring by 10% in resulting male chimeras. Male chimeras produced donor-derived offspring more fr equently (similar to 3.8 times) than female chimeras. Increases, decre ases, or no changes were observed in the frequency of donor-derived of fspring from the germline chimeras with increasing age. Male to female ratio of the offspring derived from the donor primordial germ cells d id not deviate significantly in male and female chimeras, suggesting t hat primordial germ cells that have different sex from recipient embry os could not differentiate into functional gametes. The technique for primordial germ cell transfer employed in this experiment is simple to perform and resulted in the efficient production of germline chimeras with high transmission rates of donor-derived gametes. This system pr ovides a powerful tool for avian embryo manipulation. (C) 1994 Wiley-L iss, Inc.