Eric and Janelle are carriers of the recessive allele causing Tay-Sachs disease,which is lethal in early childhood.If they have a healthy child,what is the probability that this child would NOT be a carrier of Tay-Sachs disease?
A) 1
B) 2/3
C) 1/2
D) 1/3
E) 78

Question

Quizplus · Accepted Answer

If Eric and Janelle are both carriers, their genotypes are Tt. The possible genotypes for their child are TT (not a carrier), Tt (carrier), and tt (affected). If the child is healthy, they cannot be tt, leaving TT and Tt as possibilities. The probability of being TT (not a carrier) is 1/3.

Eric and Janelle Are Carriers of the Recessive Allele Causing