Genetic linkage analyses of the blood group system loci CO, DI, DO, KEL and YT in relation to F13B indicate that these loci are not members of the RCA gene cluster on chromosome 1q32. The data are presented to finalize the exclusion of the DAF carried red cell antigens from all of the 17 established blood group systems.

Serological analysis of the red cells from members of a large French-Canadian kindred proved that the Sw^a antigen is not part of the P1, Dombrock or Yt blood group systems. A linkage analysis of the AH7 blood group locus in relation to 27 other loci indicates that SW is not closely linked to ABO, ACPI, ADA, AK1, C3, D2S5, DO, ESD, F13A, EY, GLOl, GPT, HP, IGHG, JK, LU, MYCL, PI, PGP, PGM1, PLG, RH or YT. By inference the study also allows exclusion of Sw^a from the Landsteiner-Wiener, Radin and Scianna blood group systems and exclusion of SW from the p22.1 to p34 segment of chromosome 1.