Genetics of human blood groupsPresentation Transcript
Human Blood Groups
ABO Blood Group
There are 4 blood types in ABO blood group system.
Blood Group Antigen A A B B AB A and B O Nil
Inheritance of Blood types
Human blood type is determined by co-dominant alleles.
There are three different alleles.
I A , I B and i
I A and I B are the dominant alleles and ‘ i ’ is the recessive allele.
Allele is one of the variant forms of a gene at a particular location, on a chromosome.
In an individual, one form of the allele (the dominant one) may be expressed more than another form (the recessive one).
Role of alleles
I A produces A antigen
I B produces B antigen
i produces no antigen (recessive allele)
I A and I B are co-dominant. That is, an individual with the genotype I A I B will produce both A and B antigens
Each of us has two blood type alleles. We inherit one blood type allele from our biological mother and one from our biological father. Genotype Blood Group A A B B AB O I A I A I A i I B I B I B i I A I B i i