Question

A biologist is studying the genetics of a particular species of plant. He knows that one plant may contain

hundreds of individual seeds, each of which is the result of a separate fertilization event. He determines
that seed shape is controlled by a single gene with two alleles. The dominant allele results in round seeds,
and the recessive allele results in wrinkled seeds.
In a follow-up experiment, the biologist crosses two heterozygous plants.
Which of the following is the best prediction for the frequency of wrinkled seeds that would result from
this cross?

Answer 1

25%

Step-by-step explanation:

Assuming the dominant allele that conditions round seeds is represented by R and the recessive allele that conditions wrinkle seeds is represented by r.

The biologist crossed two heterozygous plants. A heterozygous plant will contain a mixture of both alleles in its genes (Rr).

Rr x Rr = RR, 2Rr, rr

From the genotypes of the offspring, RR and Rr will appear round seeded due to the fact that R is dominant over r. Offspring with the genotype rr will appear wrinkle seeded.

Out of four of the offspring, only one will appear with wrinkled seeds. Hence,

Frequency of wrinkled seeds from the cross = 25%