DETECTION BY REVERSED-PHASE HPLC OF TRACE AMOUNTS OF THE ALPHA(113HIS) GLOBIN CHAIN IN A SHEEP HOMOZYGOUS FOR A QUADRUPLE ALPHA-GLOBIN GENECHROMOSOME

1. In sheep era alpha alpha(113His) and alpha(D) alpha alpha(113His) g lobin gene haplotypes, the percentage gene efficiencies, from the 5' t o the 3' end, are about 32-18 and 30-14-6, respectively. 2. We previou sly found that in a alpha alpha alpha alpha homozygote there may be a 1-2% alpha(113His) chains, which however were difficult to resolve fro m alpha(113Leu) chains by CMC chromatography. 3. We report here the ex perimental conditions which allowed a neat resolution of the 1% alpha( 113His) chain peak by RP-HPLC. 4. This finding strongly suggests the o ccurrence of the alpha(D) alpha alpha alpha(113His) haplotype where th e percentage gene efficiencies are 30-(14-5)-1, supporting the existen ce of a gradient of decreasing expression in multiple alpha-globin gen e haplotypes.