Offering all my points the abo blood group has three different alleles: ia, ib, and i. the genotypes and phenotypes (blood types) for different combinations of the three alleles are shown in the table possible genotype and phenotypes of abo blood group genotypes phenotypes (blood types) iaia or iai type a ibib or ibi type b ii type o iaib type ab what percentage of offspring from a cross between a homozygous type a parent with a heterozygous type a parent is expected to contain the i allele? a) 25% b) 100% c) 50% d) 75%

C (50%)

Explanation:

The ABO blood group system involves three alleles viz: IA, IB, and i.

From the question, an individual will have a Type A phenotype if the genotype is either IAIA or IAi.

Type B if the genotype is IBIB or IBi

Type O if genotype is ii

Type AB if genotype is IAIB

This shows that the alleles IA and IB are dominant over the allele i, since they both mask its expression in an heterozygous state.

N.B: Homozygous state is when an individual possess the same alleles e.g IAIA while heterozygous state is when the individual possess different alleles e.g IAi.

Also, it can be seen that alleles IA and IB exhibit co-dominance, since they are both expressed phenotypically.

Now, in a cross between homozygous type A (IAIA) and heterozygous type A (IAi) individuals (See attached image).

According to Mendel's law of segregation, the following gametes will be produced by the individual parents:

IAIA- IA and IA

IAi- IA and i

According to the cross in the attachment, 2 of the 4 possible offsprings will possess a homozygous type A genotype (IAIA) while the other 2 will possess a heterozygous type A genotype (IAi).

Hence, the percentage of offsprings expected to contain the (i) allele is 2/4 × 100 = 50%