Two people (both heterozygotes)are able to taste a chemical substance called PTC. The ability to taste PTC is caused by a dominant allele (T). The inability to taste PTC is caused by a recessive allele (t). What proportion of their children would be expected to have the tt genotype?
A)3/4
B)1/2
C)All
D)1/4
E)2/3

Question

Quizplus · Accepted Answer

Since both parents are heterozygotes (Tt), the Punnett square for their genotypes would be TT, Tt, Tt, and tt. Thus, 1 out of 4 (1/4) of their children is expected to have the tt genotype, which is recessive and results in the inability to taste PTC.

Two People (Both Heterozygotes)are Able to Taste a Chemical Substance