Avian primordial germ cells (PGCs) migrate via the extraembryonic blood fro
m the germinal crescent to the developing gonads where they differentiate i
nto spermatogonia and oogonia. PGCs thus represent a potential target cell
for the introduction of foreign DNA into the avian germline. Retroviral tra
nsduction and DNA transfection of PGCs have been successfully utilized as g
ene transfer methods to produce transgenic offspring. The advantage of PCC
methodology is the relative simplicity of the technique. A limitation of th
is approach is the need for second generation progeny to obtain birds carry
ing the transgene in all cells because the founder animal is a transgenic c
himera only in gonadal tissue.