A man with phenotype A2, Le(a+b-) shows only Lea in his saliva. Which best represents his genotype?

The genotype that best fits the description of a man with phenotype A2, Le(a+b-), and who shows only Lea in his saliva is A2O, HH, Lele, sese.

To break this down:

• The A2 phenotype indicates that the individual has at least one A2 allele, which corresponds with the genotype A2O. The presence of the O allele is not contradictory because O specifies that there is no functional A or B antigen in homozygous form.

• The Le gene dictates the presence of Lewis antigens (Lea and Leb). The phenotype Le(a+b-) means the individual can make Lea, but not Leb, which aligns with the fact that he shows only Lea in saliva. The genotype Lele confirms that he carries at least one functional Le gene, allowing for Lea production, while the sese genotype indicates he does not have the Se gene necessary for the formation of the Leb antigen.

• The HH genotype shows that he possesses the H gene necessary for the formation of the H antigen, a precursor for both A and B antigens, supporting the A2 phenotype.

The selected genotype captures the necessary components for the observed phenotype accurately: the specific ABO type, the Lewis antigen presence, and the