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Human blood type is determined by multiple alleles (A, B, and O). Which ratio would result from a cross between a man with heterozygous Type A blood and a woman with Type O blood?

User Hugmeir
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Final answer:

The offspring of a cross between a man with heterozygous Type A blood (IAi) and a woman with Type O blood (ii) will have a genotypic and phenotypic ratio of 1 Type A (IAi):1 Type O (ii).

Step-by-step explanation:

ABO Blood Typing and Inheritance Patterns

Blood type in humans is determined by multiple alleles: IA, IB, and i. The alleles IA and IB are responsible for the production of A and B antigens, respectively, on the surface of red blood cells, while the i allele does not produce any antigen. Since both A and B alleles are dominant over O (i allele), a person will have blood type A if they inherit at least one IA allele and no IB allele, type B if they inherit at least one IB allele and no IA allele, and type O if they inherit two copies of the recessive i allele.

When a man with heterozygous Type A blood (IAi) mates with a woman with Type O blood (ii), their offspring can have either Type A blood (IAi) or Type O blood (ii). The genotypic ratio would be 1:1, which also corresponds to the same ratio for their blood type expression, a 1 Type A:1 Type O phenotype ratio. This is because the offspring can either inherit an IA allele matched with an i allele from the father and an i allele from the mother, resulting in Type A blood with the genotype IAi, or inherit i alleles from both parents, resulting in Type O blood with the genotype ii.

User Valentun
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