Question

Tay-Sachs disease is a recessive genetic disorder. If only one gene is present, an individual is a carrier. What is the probability of two healthy Tay-Sachs carriers having a child that has the disease?

Answer 1

Answer:

The probability of two healthy Tay-Sachs carriers having a child that has the disease will be $25$ %

Explanation:

It is given that Tay Sachs is a recessive disorder which means the genotype must both recessive allele.

Let the dominant normal allele be T and the recessive diseased allele be t

Genotype of a healthy Tay-Sachs carriers will be Tt

Tt * Tt

TT, Tt, Tt, tt

Only child with genotype tt will have Tay-Sachs disease

Hence the probability of two healthy Tay-Sachs carriers having a child that has the disease will be $\frac{1}{4} * 100 = 25$ %