THE AMINO ACID COMPOSITION OF αT‐13 OF GLOBIN FROM A PURE BRED DINGO (CANIS FAMILIARIS DINGO)

Abstract

INTRODUGTIONThere is very little biochemical variation among the species that constitute the Ganidae (Simonsen, 1976). Studies of qualitative genetic markers in the domestic dog {Canis familiaris familiaris) and the dingo {Cf. dingo) have found no differences (Glark, Ryan and Gzuppon, 1975; Shaughnessy, Newsome and Gorbett, 1975;Gole, Baverstock and Green, 1977).The amino acid sequence of the a-chain of the haemoglobin of the domestic dog has been determined. There are two forms of the a-chain. They differ at only one position of the sequence (130), where either threonine or alanine may occur (Jones, Brimhall and Duerst, 1971). There is evidence to suggest that the presence of two forms of a-chain is widespread amongst domestic dogs and that it is coded for by multiple structural gene loci (Dresler, Brimhall and Jones, 1976). Neither the wolf {Canis lupus) nor the coyote {Canis latrans) displays evidence of this heterogeneity; their a-chains have only threonine at position 130 (Runkel et al, 1974). It has been suggested, therefore, that this change in the a-chain occurred quite recently in the evolutionary history of C.f. familiaris (Dresler et al, 1976), This paper presents the results of an examination of the amino acid composition of aT-13 (which contains residue 130) of a pure bred dingo. The presence of two forms of a-chain in the dingo further supports the conclusions that the dingo is more closely related to the domestic dog than to the wolf (Glark et al, 1975) or to the coyote (Runkel et al, 1974). MATERIALS AND METHODSBlood from a pure bred dingo was collected by venepuncture in EDTA anticoagulant. Blood was centrifuged at 3,000 g for 5 min, the plasma discarded and the red cells washed three times in isotonic saline. Globin was prepared from haemolysed red blood cells by precipitation with cold acid-acetone (Schroeder et al, 1963). The globin chains were separated on a carboxymethyl cellulose column (Whatman microgranular GM52-preswollen §Person to whom reprint requests should be sent.