The frequency of malarial infection was approximately 0.1% in the past 50 years, and the high incidence of the disease was caused by Plasmodium falciparum.[41] Mutations in glucose 6-phosphate dehydrogenase (G6PD) driven by selective pressure from malaria are known to be very common in southern China, especially to the south of 25°N latitude.[43] Therefore, we speculate that the selective pressure exerted by malaria may also have affected the gene frequencies of HLA-DRB1 in Mongolian_YN. Here, G6PD is linked to malaria.