The predicted phenotypic ratio of the offspring is 4:0 for yellow seed color. Since there are no green seed alleles (yy) in the offspring, they will all have yellow seed color, as yellow (Y) is dominant to green (y).
To predict the phenotypic ratio of the offspring based on seed color in a cross between a homozygous green seed pea plant (yy) and a heterozygous yellow seed pea plant (Yy), you can use Punnett squares. Here are the steps:
1. Determine the genotypes of the parent plants:
- Homozygous green seed pea plant (parent 1): yy
- Heterozygous yellow seed pea plant (parent 2): Yy
2. Set up a Punnett square to cross these two parent genotypes:
Parent 1 (yy)
↓
Parent 2 (Yy)
3. Fill in the Punnett square by combining the alleles from each parent:
Parent 1 (yy)
↓
Parent 2 (Yy)
yY | yY
yY | yY
4. Analyze the genotypes of the offspring:
4 offspring genotypes are yY (heterozygous yellow seed).
5. Determine the phenotypes based on the genotypes:
The yY genotype results in yellow seed color.
6. Calculate the phenotypic ratio by counting the number of each phenotype:
Yellow seed (yY): 4
Now, you have the phenotypic ratio of the offspring based on seed color:
Yellow seed (yY): 4