Question

Imagine species whose eye color is determined by receptor molecule called EyeC. When EyeC is not activaled, cAMP levels in the cell are low and yellow pigment is produced. When EyeC is activated by the binding of a signal molecule. cAMP levels rise and blue pigment is produced.

The Q allele codes for version of EyeC that responds to signal molecules and therefore turns on and off, resulting in green eye color (trom both blue and yellow pigment). The Pallele codes for version of EyeC that Is ALWAYS activated. even when signal molecules are not present.

Assuming EyeC functions similarly t0 MC1R, which of the following statements is the best prediction ol the dominance relationship between alleles and Qas well as the phenotype for PQ individuals?

a. Q is dominant Over P, and the eye color of PQ individuals is blue.

b. Q dominant over P, and the eye color of PQ individuals yellow.

c. P is dominant over Q, and the eye color of PQ individuals is blue.

d. P and Q are codominant and the eye color of PQ individuals Is green.

Answer 1

The best prediction is that the P and Q alleles are codominant, and the eye color of PQ individuals is green.

Step-by-step explanation:

The best prediction of the dominance relationship between the Q and P alleles, as well as the phenotype for PQ individuals, is option d: P and Q are codominant, and the eye color of PQ individuals is green.

In this scenario, the P allele codes for the version of EyeC that is always activated, even in the absence of signal molecules. The Q allele codes for the version of EyeC that responds to signal molecules and can turn on and off. When both alleles are present in an individual (PQ), they interact in a codominant manner, resulting in the production of both yellow and blue pigments, leading to green eye color.

Answer 2

In a hypothetical species where one allele always produces blue pigment and another turns on and off leading to green color, the continuously active allele is dominant. Consequently, individuals with both alleles would have a blue phenotype.

Step-by-step explanation:

The question involves understanding the genetics of eye color in a hypothetical species and predicting the outcomes of different allele combinations of a gene called EyeC. The allele P for EyeC is described as always active, leading to the production of a blue pigment. On the other hand, allele Q can be turned on or off by signal molecules, resulting in a combination of blue and yellow pigments, which produces green eye color.

When considering the dominance relationship between these alleles, P would likely be dominant over Q because its effect (producing the blue pigment) is always expressed, even without the signal molecule. Therefore, in a PQ individual, where both alleles are present, the phenotype would display the consequence of the dominant P allele, which is the blue pigment. Hence, the correct prediction for the phenotype of PQ individuals would be blue, since the P allele’s continuous activation overrides the Q allele’s variable response to signaling.