Genetic polymorphisms of animal complement components.

Abstract

This review summarizes current knowledge of complement polymorphisms in non-human vertebrate species. The information presented is intended to be representative of animal complement genetics in general; it is not therefore exhaustively detailed about any one specialized area. Although the majority of the genes for the human complement components have been cloned, most of the genetic data on animal complement component variation have been produced by protein studies, consequently the emphasis on the protein rather than DNA is reflected in the present discussion. The objectives of undertaking comparative genetic studies of complement are divided into two broad areas. The first concerns the evolution, the structure and regulation of the genes and gene clusters together with data relevant to their chromosomal organization in different species. The second goal is the practical one; since many complement components are highly polymorphic they have considerable intrinsic value as genetic markers. In addition, there are biomedical and veterinary aspects to be considered which draw on the knowledge of the structural and functional properties of the components in relation to physiological considerations. This review discusses the practical approaches employed in the study of animal complement variation. The data on animal complement component polymorphisms are summarized in tabular form and some of the evolutionary implications of these data are discussed. The review concludes by examining the scope for future comparative studies.