Genetics of the HL-A system in a venezuelan heterogeneous population.

HL-A antigen and gene frequencies of 206 unrelated adults living in the cities of Caracas and Maracaibo have shown that this heterogeneous Venezuelan population sample possess 11 specificities of the first (LA) HL-A series and 15 specificities of the second (Four) series. HL-A2, HL-A9, HL-A5 and W5 showed frequencies higher than those observed in caucasoid populations. The most frequent haplotypes were 2, W5; 2, 5; 9, 12; 2, 12 and 2, X2. No outstandingly high value for gametic association between the alleles of the 2 HL-A series was observed, but haplotypes formed by antigens with dissimilar frequencies in Caucasoids, Negroids and American Indian tribes have shown statistically significant D values. Genetic distance calculated using the HL-A system alone showed that this population is closer to the average Caucasoid and Negroid population tested at the 5th International Histocompatibility Workshop than to 2 American Indian tribes living in the same country.