Genetics word problem

Question

In four-o’ clock plants, the allele for red flower color has an effect that is incompletely dominant over the effect of the white color allele. If a cross between two plants produced 18 red, 32 pink, and 15 white plants, what are the phenotypes of the parents?

Answer 1

Two pink plants.

Explanation of how I solved this: Assume RR is the red plant, RW is the pink plant, and WW is the white plant.

Note the following: RR= 18, RW= 32, WW= 15.

Adding up all these numbers (18 + 32 + 15) is equal to 65.

Now, calculate the percentages of each plant.

18/65 = approximately 28%

32/65= approximately 50%

15/65= approximately 23%

This percentage correlates with a Punnet square involving two heterozygous parents, parents with one dominant allele and one recessive allele. The typical Punnet square for two heterzygous parents is 25% homozygous dominant (two dominant alleles), 50% heterozygous, and 25% homozygous recessive. You can always do a Punnett square to confirm.

                                                               R                                                                                          W

R	RR	RW
W	RW	WW