Question

n 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 with dark leaves?1 only2 and 34 only1, 2, and 3(1) gray seed color in peas is dominant to white. assume that mendel conducted a series of experiments where plants with gray seeds were crossed among themselves, and the following progeny were produced: 302 gray and 98 white. what is the most probable genotype of each parent?$gg \times gg$$gg \times gg$$gg \times gg$$gg \times gg$

Explanation:

Step1: Analyze first cross parental genotypes

True-breeding dark-leaved plant = $DD$, light-leaved = $dd$. F₁ offspring are all $Dd$.

Step2: Fill Punnett square for F₁ selfing

F₁ ($Dd$) self-pollinates:
Box1: $D \times D = DD$ (dark leaves)
Box2: $D \times d = Dd$ (dark leaves)
Box3: $d \times D = Dd$ (dark leaves)
Box4: $d \times d = dd$ (light leaves)

Step3: Analyze second cross phenotype ratio

Gray:white = $302:98 \approx 3:1$. This matches the ratio of a monohybrid cross ($Gg \times Gg$), where 3 dominant (gray) : 1 recessive (white) offspring are produced.

Answer:

1. 1, 2, and 3
2. $Gg \times Gg$