Abstract
The γ-globin chains of haemoglobin F are encoded by two non-allelic genes which synthesise two different γ-chains referred to as Gγ and Aγ. Xmn I restricts on both sides of the genes and normally produces an 8.1-kilobase (kb) fragment containing both γ-genes. A polymorphic site on the 5’ end of the Gγ genes has been reported in some populations and it results in the production of a 7.0-kb fragment containing both γ-genes.