Question

Ability to roll the tongue is caused by a dominant allele. A woman is a "roller," but one of her parents is not. Reference: Ref 6-2 The woman is expecting a child with a man who is a "nonroller." What is the probability that their child will be a "roller"?

Answer 1

1/2.

Step-by-step explanation:

The autosomal dominant trait may en defined as the trait that can express itself even in the heterozygous condition and in the homozygous dominant condition as well.

Let the B allele is responisble for the roll tongue and b is recessive allele. The woman can roll the tongue and she must have the genotype Bb because her one parents is normal. The woman married with a man with non roller ( bb). The Bb × bb cross results in the following progeny Dd, Dd ( roller), dd and dd ( non roller). The probability of the child being a roller is 1/2,

Thus, the answer is 1/2.