Question

Suggest why Ia and Ib alleles are dominant over Io allele. Why in IaIo genotype, the Io allele is masked

Answer 1

because in Ia Ib, the alleles code for proteins that synthesize a and b antigens, whereas io means no protein is produced so there are no antigens. hence in Iaio, the protein synthesizing a antigens are still translated and the red blood cell will have a antigens, thus the effect of the io allele (not having any antigens) is masked.