A student is investigating patterns of inheritance by crossing two pea plants. She creates the Punnett square shown below.

Question

image b6078e6d61974c2286abbf90ebc042f4

Which explanation of the inheritance of shape in pea plants is supported by the Punnett square?

A.
The alleles for shape show a pattern of codominance.

B.
The alleles for shape show a pattern of incomplete dominance.

C.
The allele for round shape (R) is dominant to the allele for wrinkled shape (r).

D.
The allele for wrinkled shape (r) is dominant to the allele for round shape (R).

Answer 1

To accurately evaluate the explanation of the inheritance of shape in pea plants based on the Punnett square, we need to analyze the possible offspring genotypes and phenotypes resulting from a cross between two pea plants.

Assuming the Punnett square involves a cross between a homozygous round shape plant (RR) and a homozygous wrinkled shape plant (rr), the offspring would all be heterozygous (Rr). Here, "R" represents the allele for round shape and "r" represents the allele for wrinkled shape.

Given this scenario, the correct explanation supported by the Punnett square is:

C. The allele for round shape (R) is dominant to the allele for wrinkled shape (r).

This means that all offspring (Rr) would exhibit the round shape because the dominant allele (R) masks the expression of the recessive allele (r).