The Structure of Goat Hemoglobins V. A Fourth β Chain Variant (β-D-Malta; 69 Asp ↠ Gly) with Decreased Oxygen Affinity and Occurring at a High Frequency in Malta

During a survey of hemoglobin types in goats in the Republic of Malta a variant (Goat Hb D-Malta) was discovered which differs from normal goat Hb A by the substitution of an aspartyl residue in position β 69 (E13) by a glycyl residue. The gene frequency of the βD allele was 0.255; 29 homozygous Hb D goats were present among 327 animals sampled. Homozygous Hb D goats also produce Hb C, whose β chains are the product of a non-allelic βC structural gene. Goat Hb D-Malta has a distinctly decreased affinity for molecular oxygen.