A couple is about to have a child. They are concerned about the child because of two traits caused by genes on the SAME chromosome: Tay Sachs, an autosomal recessive neurodegenerative disease, and Polydactyly, a dominant extra finger trait. The two genes are 20 map units apart. The mother has Tay Sachs but does not have polydactyly. The father is a carrier of Tay Sachs, and has polydactyly (he is heterozygous): the two dominant alleles for these phenotypes are on one chromosome, and the two recessive on the other.
Question 1 - What is the chance the child will be *phenotypically* normal, expressing neither of these traits?
A.) 5 %
B.) 6.25 %
C.) 10 %
D.) 12.5 %
E.) 20 %
F.) 25 %
G.) 50 %
Question 2 - What is the chance that the child will be a carrier for Tay Sachs?
A.) 5 %
B.) 6.25 %
C.) 10 %
D.) 12.5 %
E.) 20 %
F.) 25 %
G.) 50 %