Molecular evidence of triplication in the haptoglobin Johnson variant gene

摘要

The protein and gene structure of the Hp Johnson variant (Hp3) were analyzed in two related heterozygous individuals. The molecular weight (23kd) and amino acid composition ofHp3alpha chain were in agreement with the triplicated structure first suggested by Smithies in 1964. Direct gene analysis by Southern blotting showed a three-fold tandem repeat of the same 1.7 kb DNA segment implicated in theHp2gene duplication. On the basis of these data a nine exon model for theHp3gene is proposed.