Transferrin, alpha‐fetoprotein, and albumin in plasma of quail‐chick chimeras during embryonic development

Heterospecific chimeras obtained by blastoderm recombination between 36h quail embryos and chick yolk sacs were used as an in ovo model to determine the respective contribution of yolk sac and embryo in plasma protein during development. Analysis of quail and chick embryo plasma proteins by 2D-PAGE and peptide mapping showed that it was possible to readily distinguish both albumin and transferrin from these two avian species. No distinction could be established between chick and quail alpha-fetoprotein using these criteria. The presence of quail- and chick-type albumin and transferrin was then assayed in chimera blood at two stages of embryonic development. We show that transferrin and albumin of both avian species are found at 7 and 12 days of incubation. This result obtained in ovo suggest that both yolk sac (chick) and embryo (quail) contribute, at least, to albumin and transferrin synthesis during development.