Here's a breakdown:
* Allele: A variant form of a gene.
* Blood group antigen: A molecule on the surface of red blood cells that can trigger an immune response.
Example:
Let's consider the ABO blood group system:
* Gene: ABO gene
* Alleles: A, B, and O
* Antigens: A antigen, B antigen
An individual who is heterozygous for the ABO blood group could have the following allele combinations:
* AO: They have one A allele and one O allele. This individual would express the A antigen on their red blood cells and have blood type A.
* BO: They have one B allele and one O allele. This individual would express the B antigen on their red blood cells and have blood type B.
* AB: They have one A allele and one B allele. This individual would express both A and B antigens on their red blood cells and have blood type AB.
Importance:
Understanding heterozygosity is crucial for blood transfusion and tissue transplantation because it determines the compatibility between donor and recipient. A mismatch in antigens can lead to immune reactions, potentially causing serious complications.
In summary: Heterozygous individuals have two different alleles for a particular blood group antigen, resulting in the expression of both antigens on their red blood cells. This information is vital for determining blood type and ensuring safe blood transfusions.
