Which blood type would be completely recessive to the other types within the ABO blood group system?

Which blood type would be completely recessive to the other types within the ABO blood group system?

• A. Type A
• B. Type B
• C. Type AB
• D. Type O

Answer: (D)

In the ABO blood group system, blood type O is completely recessive to the other blood types. This means that for an individual to exhibit the O blood type, they must inherit the O allele from both parents (genotype OO). The O allele does not produce any specific antigens on the surface of red blood cells, which distinguishes it from blood types A and B, both of which have their own respective antigens (A antigen and B antigen). Conversely, blood types A and B each can be present with the O allele in heterozygous forms (genotype AO for type A and genotype BO for type B), which express the A and B antigens respectively. Blood type AB (genotype AB) expresses both A and B antigens, as it has neither an allele linked to type O nor is it capable of being recessive since both codes for the presence of antigens. Thus, type O stands out as the only blood type that does not exhibit dominance over other types, making it the completely recessive blood type when considering the ABO blood group system.

In the ABO blood group system, blood type O is completely recessive to the other blood types. This means that for an individual to exhibit the O blood type, they must inherit the O allele from both parents (genotype OO). The O allele does not produce any specific antigens on the surface of red blood cells, which distinguishes it from blood types A and B, both of which have their own respective antigens (A antigen and B antigen).

Conversely, blood types A and B each can be present with the O allele in heterozygous forms (genotype AO for type A and genotype BO for type B), which express the A and B antigens respectively. Blood type AB (genotype AB) expresses both A and B antigens, as it has neither an allele linked to type O nor is it capable of being recessive since both codes for the presence of antigens.

Thus, type O stands out as the only blood type that does not exhibit dominance over other types, making it the completely recessive blood type when considering the ABO blood group system.