Biochemical studies on haemoglobin variants of the irus macaque

Abstract

Haemolysates from 202 M . irus , imported mainly from Thailand and Vietnam, were examined by starch-gel electrophoresis. In addition to the normal haemoglobin, Hb-A mi , two major haemoglobin variants designated as Hb-P mi and Hb-Q mi and two minor components were found. Hb-P mi , which occurred in 12% of the sample, forms molecular aggregates, especially when released from the red cell. Peptide analysis showed that it differs from Hb-A mi in the absence of peptides α .TP III and α -Tp IV. Sera from animals with this haemoglobin in their red cells show two haeme-positive bands in addition to the usual single haptoglobin band; this pattern can be produced in the sera of some animals which do not possess it, by addition of Hb-P mi . Hb-Q mi , which occurred in 24% of the animals, migrates anodally to Hb-A mi at alkaline pH and does not form aggregates. It is found in two ranges of concentration when present with Hb-A mi . It was shown by recombination experiments to have normal β Ami -chains. The sample was polymorphic for a minor component which was shown to have normal β Ami chains. Some animals have two major haemoglobins and also this minor component and therefore possesses three different non- β -chains. It is suggested that the minor component is the product of a mutated duplicate of the α -locus. The population genetics of these variant haemoglobins and the possible selective role of simian malaria are discussed.