The structure of goat hemoglobins. V. A fourth beta chain variant (beta-D-Malta; 69 Asp is replaced by 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 beta 69 (E13) by a glycyl residue. The gene frequency of the beta D allele was 0.255; 29 homozygous Hb D goats were present among 327 animals sampled. Homozygous Hb D goats also produce Hb C, whose beta chains are the product of a non-allelic beta C structural gene. Goat Hb D-Malta has a distinctly decreased affinity for molecular oxygen.