Question

A botanist came across a species of plant that has two varieties of flower color: purple and white. The botanist wanted to complete several genetic crosses to determine the relationship between the two alleles. Upon crossing the different plants, the greatest majority of them were purple.
Given this information, select the statements that accurately reflect conclusions that can be made about the alleles for this trait.

The allele for purple flowers is dominant to the allele for white flowers.

In order for a plant to have white flowers, it must inherit the allele for white flowers from both parents.

In order for a plant to have purple flowers, it must inherit the allele for purple flowers from both parents.

A plant that has purple flowers can still carry an unexpressed allele for white flowers.

The allele for white flowers is dominant to the allele for purple flowers.

Answer 1

Correct choices: 1, 2, and 4.

Brief reasoning:
- If most offspring are purple, purple behaves as the dominant phenotype (1 true).
- A white phenotype must be homozygous for the recessive white allele, so a white plant must inherit a white allele from both parents (2 true).
- A purple plant does not need two purple alleles (one purple allele is sufficient), so (3) is false.
- A purple plant can be heterozygous (purple allele + unexpressed white allele), so it can carry an unexpressed white allele (4 true).
- Therefore (5) is false.

(These conclusions assume a single-gene trait with complete dominance and no complicating factors.)