Genetic variation of the sixth component of complement (C6) in the Manx shearwater (Puffinus p. puffinus).

A polymorphism in the sixth complement component (C6) has been investigated by isoelectric focusing. The results indicate that C6 is coded by genes at a single autosomal locus. Six structural alleles have been identified, a null allele is also postulated. Five island colonies of Shearwater were investigated, two alleles C6 A and C6 B predominate in all sites. The ability of rabbit C5 and C7 to combine successfully with avian C6 indicates the functional sites of these molecules are highly conserved.