How o blood group is formed?

Answer 1

Ali Al-Qhtani

The ABO antigens are terminal sugars found at the end of long sugar chains (oligosaccharides) that are attached to lipids on the red cell membrane. The expression of ABO antigens is controlled by 3 separate genetic loci:1)ABO gene located on chromosome 92)FUT1(H) gene on chromosome 193)FUT2(H) gene on chromosome 19( secretor gene)oThe expression of A or B antigens depend on H and Se genesAt least 2 genes, FUT1and FUT2oThe secretor population (80%), these antigens are found in soluble form in secretions and body fluids e.g. plasma, saliva.•They are responsible for production of H antigen •Both encode alpha 1,2 fucosyltransferase that catalyse transfer of fucoseto terminal galactose residue of the H precursor chain•FUT-1 is active in mesodermal derived tissues including hematopoietic tissues and is responsible for H expression on RBC•FUT2is responsible for the expression of H antigen on endodermaltissues including those responsible for secretion and hence the gene responsible for ABH secretion

Precursor chain of

sugars is formed most

frequently as either

Type 1 or Type 2

depending on the

linkage site between

the

N-acetylglucosamine

(G1cNAc) and

Galactose(Gal).

•Secretors are homozygous or heterozygous for the active allele (Se) ,non secretors are homozygous for the inactive allele (se).

-Type II found on RBC

Type I&II found in secretion

Answer 2

By blood group you mean blood type, and a persons' blood type is completely genetic. Type O blood with a positive Rh factor (O+) is the most common.