In humans, the trait for tongue rolling is dominant over the trait for the inability of a human to roll his/her tongue. If a heterozygous male is crossed with a homozygous recessive female, then what percent of the offspring would be expected to have the ability to roll their tongues?

Question

Responses

A100%
100%
B75%
75%
C50%
50%
D25%

Answer 1

The trait for tongue rolling is dominant, so if an individual has at least one copy of the dominant allele, they will be able to roll their tongue.

In this cross, the heterozygous male will have one dominant allele and one recessive allele for tongue rolling (Tt), while the homozygous recessive female will have two recessive alleles for the inability to roll the tongue (tt).

When these two individuals are crossed, their offspring will inherit one allele from each parent.

The possible combinations of alleles that can be inherited are: Tt and tt.

Since T is the dominant allele, all offspring with at least one T allele will be able to roll their tongues.

So, 50% of the offspring will inherit Tt and have the ability to roll their tongues.

Therefore, the correct answer is C) 50%.