Inheritance patterns of blood groups australian red. The below mentioned article provides an overview on the inheritance of blood groups in man. There are four major blood groups determined by the presence or absence of two antigens a and b on the surface of red blood cells. Blood types explained a, b, ab and o red cross blood. Within the abo blood group system, the a and b genes are codominant, i. To inherit blood group b you must receive an i b allele from one parent and either an i b or an i o allele from the other. The molecular genetic basis has been elaborated in detail over the last 15 years. When a and b are present in a heterozygote condition, the blood groups is ab as these two alleles exist as codominants. The blood groups are defined by the presence of specific. There are three versions called alleles of this gene. It comprises the largest number of antigens and the most complex genetics of all 29 known blood group systems. Inheritance of blood groups changing the genes edexcel. The o gene is silent and only expressed when neither a nor b is present. Blood groups are inherited from our parents in the same way as other genetic traits eg, eye colour.
There are three alleles which determines the a, b,o blood groups in human. The main subject of this thesis will be limited to the abo blood groups and the. Blood group oif you belong to the blood group o,you have neither a or b antigens onthe surface of your rbcs but you haveboth a and b antibodies in your bloodplasma. Therefore, the inheritance pattern looks paradoxical, whereas in fact, it exactly follows the general mendelian inheritance of abo blood groups. There are four common blood groups in the abo system. One copy is inherited from our mother, the other from our father. Rhesus is the most important protein based blood group system, clinically. Genetic characterisation of human abo blood group variants with.
Pdf principle of blood group inheritance and calculation of its. Blood type inheritance is more complicated than typical mendelian inheritance, where there are only two alleles. The genetics of blood type 2006 blood type is an example of a trait determined by a single gene. Generally a gene has two alternative forms or alleles, one in each of the homologous chromosomes. Inheritance patterns of blood groups australian red cross lifeblood. Each of us has two copies of the gene for blood type on chromosome pair number 9. Such an explanation will not, however, serve for the antigen.
Blood groups are inherited from our biological parents in the same way as eye colour and other genetic traits. The final step in the enzymatic synthesis of the aboh blood group a and b antigens is catalyzed by two closely related glycosyltransferases, an alpha nacetylgalactosaminyltransferase gta and an alpha galactosyltransferase gtb. Inheritance of blood groups new zealand blood service. Abo and rh are the most wellknown among the blood group systems.