In determining the phenotype for the ABO blood system...

Question

Responses

O is dominant over A
O is dominant over A

B is dominant over A
B is dominant over A

O is recessive
O is recessive

A is dominant over B

Answer 1

In the ABO blood system, the phenotypes are determined by the alleles A, B, and O. Here's how they relate:

1. O is recessive - This means that for an individual to have blood type O, they must have two O alleles (genotype OO).

2. A is dominant over O - An individual with genotype AO or AA will have blood type A.

3. B is dominant over O - An individual with genotype BO or BB will have blood type B.

4. A and B are co-dominant - An individual with one A allele and one B allele (genotype AB) will have blood type AB.

To clarify the statements provided in your query:

• O is dominant over A - This is false (O is actually recessive).
• B is dominant over A - This is false (A and B are codominant).
• O is recessive - This is true.
• A is dominant over B - This is false (they are codominant).

So, the only accurate statement from your list is: O is recessive.