Answers are grounded in this paper and cite their sources.
Immunoelectrophoretic comparison of maternal and fetal rat serum proteins with antiserum to adult rat serum proteins showed a unique protein in the fetal serum. The fetal protein exhibited in agar gel electrophoresis a variable mobility that was dependent on concentration. The fetal protein reacted strongly with a nonspecific antiserum.
No takes yet. Share an insight, caveat, or question.
Kelleher et al. (1962) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: