Certainly! To predict the genotype of the offspring when a plant heterozygous for yellow seeds is crossed with a plant homozygous for green seeds, we need to apply the principles of Mendelian genetics. Here is a detailed step-by-step solution using a Punnett square:
1. Identify the genotypes of the parents:
- The heterozygous plant for yellow seeds has the genotype [tex]\(Yy\)[/tex] (where "Y" represents the dominant allele for yellow seeds and "y" represents the recessive allele for green seeds).
- The homozygous plant for green seeds has the genotype [tex]\(yy\)[/tex].
2. Set up the Punnett square:
- Since the Punnett square helps us visualize the possible genotypes of the offspring, we set up a grid.
- The alleles from one parent (the heterozygous [tex]\(Yy\)[/tex] plant) are placed on the top of the grid.
- The alleles from the other parent (the homozygous [tex]\(yy\)[/tex] plant) are placed along the side of the grid.
The Punnett square will look like this:
| | Y | y |
|---|---|---|
| y | | |
| y | | |
3. Fill in the Punnett square:
- For each cell in the grid, combine the alleles from the top and side.
- Top left cell: [tex]\(Y\)[/tex] (from the top) and [tex]\(y\)[/tex] (from the side) combine to form [tex]\(Yy\)[/tex].
- Top right cell: [tex]\(y\)[/tex] (from the top) and [tex]\(y\)[/tex] (from the side) combine to form [tex]\(yy\)[/tex].
- Bottom left cell: [tex]\(Y\)[/tex] (from the top) and [tex]\(y\)[/tex] (from the side) combine to form [tex]\(Yy\)[/tex].
- Bottom right cell: [tex]\(y\)[/tex] (from the top) and [tex]\(y\)[/tex] (from the side) combine to form [tex]\(yy\)[/tex].
The completed Punnett square:
| | Y | y |
|---|---|---|
| y | Yy| yy|
| y | Yy| yy|
4. Determine the genotypes of the offspring:
- From the Punnett square, we see that there are two possible genotypes for the offspring:
- [tex]\(Yy\)[/tex] (heterozygous for yellow seeds)
- [tex]\(yy\)[/tex] (homozygous for green seeds)
5. Calculate the genotype ratio:
- There are four possible combinations.
- Two out of the four combinations form [tex]\(Yy\)[/tex].
- Two out of the four combinations form [tex]\(yy\)[/tex].
Therefore, the genotype ratio of the offspring is:
[tex]\[
Yy : yy = 2 : 2 \quad \text{or simplified} \quad 1 : 1
\][/tex]
6. Done: The offspring will have a 1:1 ratio of heterozygous yellow seeds ([tex]\(Yy\)[/tex]) to homozygous green seeds ([tex]\(yy\)[/tex]).
The predicted genotypes of the offspring are equally likely to be [tex]\(Yy\)[/tex] or [tex]\(yy\)[/tex] resulting in a 1:1 ratio.
