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

Question

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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 determine which explanation of the inheritance of shape in pea plants is supported by the Punnett square, we need to analyze the typical allelic relationships for the traits involved.

In pea plants:

• The round shape (R) is dominant over the wrinkled shape (r).

If the Punnett square is set up with one parent being homozygous for round shape (RR) and the other being homozygous for wrinkled shape (rr), the resulting offspring would all be heterozygous (Rr) and exhibit the round shape due to the dominance of the R allele.

Based on the information provided, the most likely 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 explains why the offspring would show the round shape if one parent is round (RR) and the other is wrinkled (rr).