Hæmoglobin F and the Genetic Control of Protein Structure

Abstract

THE publication of a hypothesis concerning hæmoglobin synthesis presented recently in Nature by Drs. Zuelzer and Robinson¹ prompts me to comment briefly. Their article concerns the genetic control of the synthesis of the peptide chains of the human hæmoglobins : A (adult) = α₂β₂, F (fœtal) = α₂γ₂, and A ₂ (the minor adult hæmoglobin) = α₂δ₂. The symbols α, β, γ, δ are used to denote the peptide chains of which the hæmoglobin molecules are composed and also the genes controlling their structure. The authors propose that “the production of γ-chains is under the control of the same pair of genes which determines the formation of β-chains, once the maturation of the fœtus has reached the point where adult hæmoglobin can be made”. Again, in cases of thalassæmia, for example, where there seemed to be a block in the synthesis of β-chains due to a substitution in the chain, “the simplest possible assumption seemed to be that the character or site of the substitution in the β-chain itself determined the nature of the by-product, γ or δ, accumulating in consequence of a block in the metabolic pathway of β-chain synthesis”.