In a dihybrid Punnett Square, when crossing two parents who are heterozygous for both traits, which of the following statements would be correct about the offspring?

Question

Choose TWO correct answers.

The phenotypic ratio would be twelve:four:zero:zero.

Less than half of the offspring would show one of the two recessive phenotypes.

The majority of the offspring would show the dominant phenotype.

The majority of the offspring would be have the same genotype as both parents.

The phenotypic ratio would be nine:three:three:one.

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Answer 1

In a dihybrid cross between two parents who are heterozygous for both traits (e.g., AaBb x AaBb), the following statements are correct:

1. Less than half of the offspring would show one of the two recessive phenotypes. - This is true because for a dihybrid cross, the expected ratio of offspring showing both recessive phenotypes (aa and bb) is significantly lower than half.

2. The phenotypic ratio would be nine:three:three:one. - This is the standard phenotypic ratio resulting from a dihybrid cross, where 9 show both dominant traits, 3 show the first dominant trait and the second recessive trait, 3 show the first recessive and the second dominant trait, and 1 shows both recessive traits.

Thus, the two correct statements are:

• Less than half of the offspring would show one of the two recessive phenotypes.
• The phenotypic ratio would be nine:three:three:one.