Forensic application of blood stains and polymorphism of the sixth component of human complement (C6).

Blood samples from 340 unrelated individuals in Fukui prefecture in the central part of Japan were tested in order to determine the gene frequencies of the C6 common alleles. The gene frequencies calculated were as follows: C6 A, 0.478, C6 B, 0.464, C6 B2, 0.052 and rare alleles, 0.006. It was demonstrated that C6 phenotyping from blood stains aged over a period of 1 year, could be performed correctly. The quantity of detectable whole blood after this period amounted to less than 2 microliter.