9 Hands-On Worksheet Punnett Square Worksheet - The Teach Simple Blog - Free Printable

Problem Overview:

The task involves completing Punnett squares for different parent combinations and determining the possible genotypes of their offspring. The alleles are defined as follows:
- T: Dominant allele for tall plants
- t: Recessive allele for short plants

The phenotypes are determined by the following rules:
1. TT: Dominant tall (genotype: tall, phenotype: tall)
2. Tt: Mixed hybrid (genotype: hybrid, phenotype: tall)
3. tt: Recessive short (genotype: short, phenotype: short)

We need to fill in the Punnett squares and determine the possible offspring for each parent combination.

---

Step-by-Step Solution:

#### 1. Both parents are dominant tall (TT × TT)

- Parent 1: TT
- Parent 2: TT

The Punnett square is constructed as follows:
```
T T
┌─────┬─────┐
T │ TT │ TT │
├─────┼─────┤
T │ TT │ TT │
└─────┴─────┘
```

- Possible offspring: All are TT.
- Phenotypes: All are tall.

#### 2. Both parents are mixed hybrid (Tt × Tt)

- Parent 1: Tt
- Parent 2: Tt

The Punnett square is constructed as follows:
```
T t
┌─────┬─────┐
T │ TT │ Tt │
├─────┼─────┤
t │ Tt │ tt │
└─────┴─────┘
```

- Possible offspring:
1. TT (tall)
2. Tt (tall)
3. Tt (tall)
4. tt (short)

- Expected ratio: 3 tall : 1 short.

#### 3. One parent is dominant tall (TT), one is mixed hybrid (Tt)

- Parent 1: TT
- Parent 2: Tt

The Punnett square is constructed as follows:
```
T t
┌─────┬─────┐
T │ TT │ Tt │
├─────┼─────┤
T │ TT │ Tt │
└─────┴─────┘
```

- Possible offspring:
1. TT (tall)
2. Tt (tall)
3. TT (tall)
4. Tt (tall)

- All offspring will be tall.

#### 4. Both parents are recessive short (tt × tt)

- Parent 1: tt
- Parent 2: tt

The Punnett square is constructed as follows:
```
t t
┌─────┬─────┐
t │ tt │ tt │
├─────┼─────┤
t │ tt │ tt │
└─────┴─────┘
```

- Possible offspring: All are tt.
- Phenotypes: All are short.

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Final Answer:

1. Both parents are dominant tall (TT × TT):
- Offspring: TT, TT, TT, TT
- Phenotypes: All tall

2. Both parents are mixed hybrid (Tt × Tt):
- Offspring: TT, Tt, Tt, tt
- Phenotypes: 3 tall, 1 short
- Ratio: 3:1

3. One parent is dominant tall (TT), one is mixed hybrid (Tt):
- Offspring: TT, Tt, TT, Tt
- Phenotypes: All tall

4. Both parents are recessive short (tt × tt):
- Offspring: tt, tt, tt, tt
- Phenotypes: All short

Final Answer Boxed:
\[
\boxed{
\begin{array}{l}
\text{1. TT, TT, TT, TT (All tall)} \\
\text{2. TT, Tt, Tt, tt (3 tall, 1 short; 3:1 ratio)} \\
\text{3. TT, Tt, TT, Tt (All tall)} \\
\text{4. tt, tt, tt, tt (All short)}
\end{array}
}
\]