IN-SITU HYBRIDIZATION ANALYSIS OF GLOBIN MESSENGER-RNAS IN THE PRIMITIVE ERYTHROID-CELLS OF THE CHICK-EMBRYO

The possibility that the minor embryonic chick hemoglobins might be pr esent in a particular subgroup of primitive erythroid cells has been i nvestigated by in situ hybridization. Probe to detect the mRNA for the alpha(A) globin chain of the minor embryonic hemoglobin was used, and the results of the hybridization were compared with those obtained us ing as probes the cDNAs for total globin mRNAs. All erythroid cells ci rculating in a 4-day-old chick embryo gave positive signals with both probes at an approximately constant, ratio. This shows that all cells contain a similar assortment of hemoglobin types, excluding the possib ility that a subgroup might contain the minor primitive hemoglobins ex clusively. However, the cells are not homogeneous, since about 10% of them show a distinctly higher concentration of mRNA of all globin type s.