Inheritance pattern of ABO blood groups in humans show dominance , co - dominance and multiple allelism. Explain each concept with the help of blood group genotypes.
Inheritance pattern of ABO blood groups in humans show dominance , codominance and multiple allelism can be explained as
- In dominance, F1 progeny resembles one of the parent.
- In co-dominance, the F1 progeny resembles both the parents
- Multiple alleles: When more than two alleles control a character, as in human blood groups
- Example: ABO blood groups in human beings
- ABO blood groups are controlled by gene I. Gene I has three alleles, I A, I B and i. A person possesses any two of the three alleles.
- IA and I B dominate over i. But with each other, IA and IB are co-dominant.
-
IA and I B contain A and B types of sugar, while i does not contain any sugar.
Allele from Parent 1
Allele from Parent 2
Genotype of offspring
Blood type of offspring
I A
I A
I A I A
A
I A
I B
I A I B
AB
I A
i
I A i
A
I B
I A
I A I B
AB
I B
I B
I B I B
B
I B
i
I B i
B
i
i
i i
O