Question

The ability to roll the tongue (R) is determined by a dominant gene while the recessive gene results in the ability to roll the tongue (r). A man and his wife can both roll their tongues and are surprised to find that their son cannot. Explain this by showing the genotypes of all three pesons.

I think both the mother and the father's genotypes are Rr (heterozygous).
And the child probably has a homozygous recessive trait (rr).

Am I right?
Please check!
Thanks!

Answer 1

The first sentence should read:
The ability to roll the tongue (R) is determined by a dominant gene while the recessive gene results in the inability to roll the tongue (r).

(INability)*