Use the figure and the following description to answer the question.
In a particular plant, leaf color is controlled by gene locus D. Plants with at least one allele D have dark green leaves, and plants with the homozygous recessive dd genotype have light green leaves. A true-breeding, dark-leaved plant is crossed with a light-leaved one, and the F₁ offspring is allowed to self-pollinate. The predicted outcome of the F₂ is diagrammed in the Punnett square shown in the figure, where 1, 2, 3, and 4 represent the genotypes corresponding to each box within the square.

Which of the boxes marked 1-4 correspond to plants that will be true-breeding?

Question

Use the figure and the following description to answer the question.
In a particular plant, leaf color is controlled by gene locus D. Plants with at least one allele D have dark green leaves, and plants with the homozygous recessive dd genotype have light green leaves. A true-breeding, dark-leaved plant is crossed with a light-leaved one, and the F₁ offspring is allowed to self-pollinate. The predicted outcome of the F₂ is diagrammed in the Punnett square shown in the figure, where 1, 2, 3, and 4 represent the genotypes corresponding to each box within the square.

Which of the boxes marked 1-4 correspond to plants that will be true-breeding?

Quizplus · Accepted Answer

True-breeding means that the genotype of the offspring will be the same as its parents. Only the homozygous parents can produce true-breeding offspring. In this case, box 1 corresponds to the homozygous dominant (DD) genotype and box 4 corresponds to the homozygous recessive (dd) genotype. Both of these genotypes are homozygous, so the offspring will be true-breeding if they inherit the same allele from their parents. Boxes 2 and 3 are heterozygous, so the offspring will not be true-breeding.

Use the Figure and the Following Description to Answer the Question