Question

Imagine that the donut is a sexually reproducing animal and that a single enzyme forms the hole. All donuts observed in the past have had holes. Suppose a mutation occurs in one gene of the donut such that it now codes for an inactive protein instead of the hole-forming enzyme. Which of the following predictions would be most likely in descendants of this mutant donut? For each prediction, explain whether or not it would be a likely prediction.

a. All members of the next generation will have holes

b. Heterozygous donuts will not have holes

c. If the cell in which the mutation occurs undergoes mitosis, subsequent generations of donuts will all have holes

d. The next generation will all be holeless

e.Past generations of donuts have all had holes

Answer 1

Solutions

1. This would a likely prediction. Since the donut is sexually producing, it would have at the least two copies of the allele. This means that the mutant donut would mate with a normal donut. The normal allele would ensure that functional enzyme is produced, thereby leading to formation of holes.

2. This is not a likely prediction. Since heterozygotes will have two copies of the alleles (one normal, and one mutant), the functional enzyme will be produced, and the donut will show presence of a hole.

3. This is not a likely prediction. If the cell undergoes mitosis, two copies of the mutant allele would be produced, and each will be passed onto the daughter donuts, making them dysfunctional as well, and without holes.

4. This is a not a likely prediction. Since the assumption is that the mutant will mate with a normal species. The functional allele from the normal parent would ensure that next generation would be carriers, but with holes.

5. This is a likely prediction. It has been confirmed through observations, as mentioned in the question statement itself.