In a specific scenario, red flowers are dominant over white flowers. A plant heterozygous for red flowers and a plant with white flowers are crossed. What is the expected proportion of phenotypes in the next generation?

Rationale

A) 2 red, 2 white is the correct expected proportion of phenotypes in the next generation.

When a plant heterozygous for red flowers (Rr) is crossed with a plant with white flowers (rr), the expected proportion of phenotypes in the next generation would be 2 red flowers and 2 white flowers. This is because the heterozygous plant will contribute one R allele and one r allele, while the white flower plant will contribute two r alleles.

B (3 red, 1 white) YOUR ANSWER

This ratio would be expected if a homozygous dominant red flower (RR) was crossed with a heterozygous red flower (Rr). However, in this case, one of the parents is a white flower plant (rr), which can only contribute recessive alleles. Therefore, this ratio is incorrect.

C (4 red, 0 white) YOUR ANSWER

This ratio would be expected if both parents were homozygous for the red flower trait (RR). However, in this case, one of the parents is a white flower plant (rr), which can only contribute recessive alleles. Therefore, there will be some offspring with white flowers and this ratio is incorrect.

D (1 red, 3 white) YOUR ANSWER

This ratio would be expected if a homozygous dominant red flower (RR) was crossed with a homozygous recessive white flower (rr). However, in this case, one of the parents is a heterozygous red flower plant (Rr), which can contribute both dominant and recessive alleles. Therefore, this ratio is incorrect.

Conclusion

When a heterozygous red flower (Rr) is crossed with a white flower (rr), each parent contributes one allele to each offspring. The heterozygous parent can contribute either a dominant (R) or recessive (r) allele, while the homozygous recessive parent can only contribute a recessive (r) allele. This results in an expected phenotype ratio of 2 red: 2 white flowers in the next generation.

In a specific scenario, red flowers are dominant over white flowers. A plant heterozygous for red flowers and a plant with white flowers are crossed. What is the expected proportion of phenotypes in the next generation?

A) 2 red, 2 white is the correct expected proportion of phenotypes in the next generation.

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