In humans, the ability to roll one's tongue follows the dominant/recessive pattern of inheritance. The allele for tongue-rolling is dominant to the allele for non-tongue-rolling. If two homozygous parents can roll their tongues, what is the probability that their child will also be able to?

Question

In humans, the ability to roll one's tongue follows the dominant/recessive pattern of inheritance. The allele for tongue-rolling is dominant to the allele for non-tongue-rolling. If two homozygous parents can roll their tongues, what is the probability that their child will also be able to?

Hint: Use the Punnett Square below to help you.
R R
R ? ?
R ? ?
A.
50%
B.
0%
C.
75%
D.
100%

Answer 1

C. 75%

When both parents are homozygous for the dominant allele (RR), all of their offspring will inherit at least one dominant allele for tongue-rolling. Therefore, the probability that their child will be able to roll their tongue is 75%.