If observable HLA haplotypes occur more commonly in certain populations than would statistically be considered normally, this process is known as linkage disequilibrium. Populations that are large, diverse, and undergo random mating can obtain genetic equilibrium after a couple generations, unless a selection type event occurs.
We can use data from the Alleles Frequency website
to observe linkage disequilibrium in a population:
The sample (n) is 11,407.
The A*02 allele frequency is 0.2921.
The B*07 has an allele frequency of 0.1310.
The likelihood of inheritance should be (A*02 x B*07) x 100.
(0.2921 x 0.1310) x 100 = 3.826% for this geographic population.
However, the population has HLA A*02 = 49.9% and HLA B*07 =24.5%.
This finding is far above statistical likelihood and suggests linkage disequilibrium. This concept is important to consider when searching for donor populations for organ and bone marrow matches for transplantation.