Question

D)Two different plants are crossed. One has the genotype tt and the other has the genotype Tt. Fill in the Punnett square below for this cross. Remember, one parent allele goes in each space on the top and side. (1 point)

e) What is the genotype ratio for this cross? (1 point)

f) What is the phenotype ratio for this cross? (1 point)

Answer 1

d) The Punnett square for the cross between two plants with genotype tt and Tt is shown below:

T | t

--|--

t | Tt

t | tt

t | t

--|--

t | tt

t | tt

e) The genotype ratio for this cross is 1:1 (Tt:tt) as shown in the Punnett square.

f) The phenotype ratio for this cross is 1:1 (tall:short). All the offspring will have short stems because the tt genotype is homozygous recessive and the Tt genotype is heterozygous. The expression of the T allele masks the expression of the t allele in heterozygotes, so the offspring will all have the recessive phenotype.