FUT2 and infection: “The relatively high allele frequency for some of the FUT2-null alleles is likely an evolutionary advantage when the soluble and/or mucosal H antigens are absent, and the presence of H determinants on mucosal surfaces may be more biologically important than their cellular analogs, various reports of the increased resistance to infection by a wide range of pathogens in individuals of the nonsecretor phenotype supported the observations (18–21).”