Question

In humans, being a tongue roller (R) is dominant over non-roller (1). A man who is a non-roller marries a woman who is heterozygous for tongue rolling.

Answer 1

Answer:

This question is incomplete, the complete part of the question is as follows:

1. Father’s phenotype _______ Father’s genotype ______

2. Mother’s phenotype ________ Mother’s genotype _______

3. What is the probability of this couple having a child who is a tongue roller?

- Father's phenotype is NON-ROLLER, while his genotype is rr.

- Mother's phenotype is ROLLER while her genotype is Rr

- The probability of this couple having a child who is a tongue roller is 50% or 1/2.

Explanation:

This question involves a single gene coding for the ability or not to roll the to tongue in humans. The alelle for tongue roller (R) is dominant over the allele for non-roller (r). This means an heterozygote individual (Rr) will be able a tongue roller.

According to this question, a man who is a non-roller (rr) marries a woman who is heterozygous for tongue rolling (Rr) i.e. rr × Rr. The following gametes will be produced by each parent:

rr - r and r

Rr - R and r

Using these gametes in a punnet square (see attached image), the following proportion of offsprings will be produced:

Rr, Rr, rr and rr

- Offsprings with genotype Rr (1/2 or 50%) will be tongue rollers

- Offsprings with genotype rr (1/2 or 50%) will be non-tongue rollers.

Hence, based on this question;

- Father's phenotype is NON-ROLLER, while his genotype is rr.

- Mother's phenotype is ROLLER while her genotype is Rr

- The probability of this couple having a child who is a tongue roller is 50% or 1/2