Transferrin Variation Between Mother and Fetus in the Marsupial, Macropus Eugenii

The placenta of the tammar wallaby, like that of most marsupials, is formed by close apposition of the yolk-sac membrane to the uterine epithelium. The yolk-sac fluid is rich in a variety of substances such as amino acids, glucose and protein which change quantitatively and qualitatively throughout gestation, the most marked changes occurring after attachment of the membrane to the uterus (Renfree, 1970). Since many of the proteins resemble maternal proteins, they may have been transferred unchanged after attachment; conversely, they may have been synthesized by the embryo and the similarities may be due to the genetic similarities of the embryo and its mother. We have examined these two possibilities in the β-globulin proteins of yolk-sac fluid. The transferrins in this moiety of serum can be detected by virtue of their capacity to