Blood Group Inheritance

BLOOD GROUP INHERITANCE

  •     Blood Types:

- Human blood is categorized into different blood types based on the presence or absence of specific antigens on the surface of red blood cells.

- The ABO blood group system and the Rh factor (Rhesus factor) are the most important for blood type determination.

  •  ABO Blood Group System:

- The ABO system has four main blood types: A, B, AB, and O.

- Blood type is determined by the presence or absence of antigens (A and B) on the red blood cell surface.

- Genes responsible for blood type are located on chromosome 9.

- Blood type inheritance follows Mendelian principles.

  •  ABO Inheritance:

- Individuals inherit one allele from each parent, resulting in three possible genotypes: AA, AO, BB, BO, AB, and OO.

- The alleles A and B are codominant, while O is recessive.

- Genotype AO or BO results in blood type A or B, respectively, and AA or BB leads to the corresponding type.

- Genotype AB results in blood type AB, and OO leads to blood type O.

  •  Rh Factor (Rhesus Factor):

- The Rh factor is another antigen found on the surface of red blood cells.

- Individuals who have this antigen are Rh-positive (e.g., A+, B+), while those lacking it are Rh-negative (e.g., A-, B-).

- The Rh factor is inherited independently of the ABO blood group system.

  • Rh Inheritance:

- The presence or absence of the Rh factor is determined by the RhD gene located on chromosome 1.

- It follows a Mendelian inheritance pattern, with Rh-positive being dominant over Rh-negative.

- Inheritance of Rh factor is unrelated to ABO blood type inheritance.

  • Compatibility and Blood Transfusions:

- Blood compatibility is crucial for safe blood transfusions.

- Transfusion with incompatible blood can lead to agglutination (clumping) and serious health risks.

  • Importance in Medicine:

- Understanding blood group inheritance is vital for blood transfusion, organ transplantation, and prenatal care to prevent hemolytic disease of the newborn (HDN).

  • Universal Donors and Recipients:

- Type O- individuals are universal blood donors as their blood lacks A, B, and Rh antigens.

- Type AB+ individuals are universal recipients as they can receive blood from all ABO and Rh groups.