Question

background: the allele for blood type a is represented by the designation i^a and the allele for blood type b is designated as i^b. both of these alleles are dominant to blood type o, which is designated i. they are codominant to each other.

• what are the two possible genotypes for blood type a?
• what are the two possible genotypes for blood type b?
• what is the only possible genotype for blood type ab?
• what is the only possible genotype for blood type o?

work the following problems:
(there are two punnett squares and related questions about the number of different blood type individuals and carriers)
how many type a individuals
how many type ab individuals
how many type b individuals
carriers of o type
what are the blood types of the above parents?
how many type a individuals
how many type ab individuals
how many type b individuals
carriers of o type
what are the blood types of the above parents?

Explanation:

• For blood type A: Since \(I^{A}\) is dominant over \(i\), the genotypes \(I^{A}I^{A}\) (homozygous) and \(I^{A}i\) (heterozygous) will result in blood type A.
• For blood type B: As \(I^{B}\) is dominant over \(i\), the genotypes \(I^{B}I^{B}\) (homozygous) and \(I^{B}i\) (heterozygous) lead to blood type B.
• For blood type AB: Due to codominance of \(I^{A}\) and \(I^{B}\), only the genotype \(I^{A}I^{B}\) gives blood type AB.
• For blood type O: Since \(i\) is recessive, only the homozygous \(ii\) genotype results in blood type O.

Answer:

• Two possible genotypes for blood type A: \(I^{A}I^{A}\), \(I^{A}i\)
• Two possible genotypes for blood type B: \(I^{B}I^{B}\), \(I^{B}i\)
• Only possible genotype for blood type AB: \(I^{A}I^{B}\)
• Only possible genotype for blood type O: \(ii\)