Inheritance of ABO Blood Groups
ABO blood group system is an inheritable characteristic that is transmitted from parents to offspring.
The ABO blood groups have three genes involved, a case of multiple alleles and are responsible for the presence of antigen types on the Red Blood Cells.
Multiple alleles; a set of more than two alleles that may determine a character; e.g. ABO Blood group system.
Gene A is responsible for the presence of antigen A.
Gene B is responsible for the presence of antigen B.
Gene O is responsible for no (zero) antigen on the RBCs.
The genotypes of the four blood groups in the ABO system are thus formed by allelic pairs of genes.
|
Blood group (phenotype) |
Genotype |
Antigens |
|
A |
AA, AO |
A |
|
B |
BB, BO |
B |
|
AB |
AB |
A and B |
|
O |
OO |
0 (Zero) |
The marriage between a man who is heterozygous for blood group A and a woman who is heterozygous for blood group B will produce children of all four blood groups.
A man who is homozygous for blood group A married to a woman who is homozygous for blood group B would produce children who would only be AB.
However, a marriage between a man of blood group A and a woman of the same blood group cannot produce children of blood group B. Likewise, a man of blood group B and a woman of blood group B cannot produce children of blood group A. Parents who belong to blood group O cannot produce children with blood group A or B.
