COMPLEMENT C6 AND C7 DNA POLYMORPHISMS ANALYZED BY PCR IN 7 ETHNIC-GROUPS AND CHARACTERIZATION OF THE C6 MSPI RFLP

Five polymorphisms in the C6 and C7 genes have been investigated in se ven ethnic groups, The allele frequencies are broadly similar in most groups except C7 M/N which is monomorphic in our group of Africans, aa d C6 MspI and C7 S367T where the allele frequencies in African and Cap e Coloured subjects are very different from the other ethnic groups. T here is very little allelic association except between C6 A/B and C6 M spI, Seventeen of the 32 possible haplotypes have been observed, sugge sting that much recombination has taken place. We describe a new metho d for the investigation of the MspI RFLP located in intron 3 of C6 (ap proximately 3 kbp 3' from exon 3 and 1.5 kbp 5' from exon 4) and its m olecular basis, together with an improved method for the isolation of DNA from stored serum.