Question

In four o'slocks, flowers may be red if the red allele is homozygous or yellow if the yellow allele is homozygous. The two alleles are incompletely dominant to each other. Leaf margin pattern is also controlled by one gene. Entire is completely dominant over lobe. A yellow flowered hybrid entire plant is crossed with an orange flowered lobed plant. What are the genotypes of the two parents? What will be the expected genotypes and phenotypes of the offspring from this cross?

Answer 1

The genotypes of the two parents are as follows:

- The yellow flowered hybrid entire plant is heterozygous for flower color, having one yellow allele (Y) and one red allele (R), and is homozygous for leaf margin pattern, having two copies of the dominant entire allele (E).
- The orange flowered lobed plant is homozygous for flower color, having two copies of the recessive orange allele (O), and is heterozygous for leaf margin pattern, having one copy of the dominant entire allele (E) and one copy of the recessive lobe allele (L).

When these two parents are crossed, the possible genotypes and phenotypes of the offspring can be determined using Punnett square analysis.

- Genotypes of the offspring:
- 25% will be YOEE (yellow flowers, entire leaf margin)
- 25% will be YOLE (yellow flowers, lobe leaf margin)
- 25% will be ROEE (red flowers, entire leaf margin)
- 25% will be ROLE (red flowers, lobe leaf margin)

- Phenotypes of the offspring:
- 50% will have yellow flowers
- 50% will have red flowers
- 75% will have entire leaf margin
- 25% will have lobe leaf margin

These ratios are based on the inheritance patterns of the flower color and leaf margin genes, as described in the question.