Stability of the individual globin genes during erythroid differentiation.

The genes of sheep betaA, betaC, and gamma globin were all present in DNA from erythroid cells which synthesized only betaC globin. Similarly, selective excision of non-expressed genes was shown not to occur during human erythroid differentiation. In contrast, evolutionary deletion of the betaC gene accounts for the inability of many sheep to make this globin.