Question

14. In the human ABO blood group system, there are six possible genotypes but only four
phenotypes. An explanation of this is that the ABO blood groups are controlled by
(a) One gene locus with three codominant alleles
(b) One gene locus with two codominant alleles and two recessive alleles.
(c) One gene locus with two codoininant alleles and one recessive allele.
(d) Two unlinked gene loci each with two alleles, one dominant and one recessive.​

Answer 1

Answer:

one gene locus with two codominant alleles and one recessive allele