15 Punnett Square Worksheet Answer Key - Free Printable

Problem Overview:

The task involves completing Punnett squares for various genetic crosses. A Punnett square is a tool used in genetics to predict the probability of offspring inheriting specific traits based on the genotypes of the parents. The rules provided in the image are:

1. Dominant genes are represented by uppercase letters (e.g., \( B \)).
2. Recessive genes are represented by lowercase letters (e.g., \( b \)).
3. If a child's genotype is a hybrid, the dominant gene is placed first (e.g., \( Bb \)).
4. For parents, the dominant gene (if present) is listed first in the genotype.

Solution Approach:

We will solve each Punnett square step by step, following these guidelines:

#### Step 1: Understand the Genotypes
- Each parent contributes one allele to the offspring.
- The alleles from each parent are combined to form the offspring's genotype.

#### Step 2: Fill in the Punnett Square
- Place the alleles from one parent along the top row.
- Place the alleles from the other parent along the left column.
- Fill in the boxes by combining one allele from the top with one allele from the side.

#### Step 3: Determine the Genotypes
- Write the resulting genotypes in the boxes.
- Ensure that dominant alleles are written first in hybrids.

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Detailed Solutions for Each Punnett Square:

#### Square 1:
Parents: \( B \) and \( B \)
- Top row: \( B \), \( B \)
- Left column: \( B \), \( B \)

| | \( B \) | \( B \) |
|---|--------|--------|
| \( B \) | \( BB \) | \( BB \) |
| \( B \) | \( BB \) | \( BB \) |

Result: All offspring have the genotype \( BB \).

#### Square 2:
Parents: \( B \) and \( b \)
- Top row: \( B \), \( b \)
- Left column: \( B \), \( b \)

| | \( B \) | \( b \) |
|---|--------|--------|
| \( B \) | \( BB \) | \( Bb \) |
| \( b \) | \( Bb \) | \( bb \) |

Result: Offspring genotypes are \( BB \), \( Bb \), \( Bb \), \( bb \).

#### Square 3:
Parents: \( b \) and \( b \)
- Top row: \( b \), \( b \)
- Left column: \( b \), \( b \)

| | \( b \) | \( b \) |
|---|--------|--------|
| \( b \) | \( bb \) | \( bb \) |
| \( b \) | \( bb \) | \( bb \) |

Result: All offspring have the genotype \( bb \).

#### Square 4:
Parents: \( E \) and \( e \)
- Top row: \( E \), \( e \)
- Left column: \( E \), \( e \)

| | \( E \) | \( e \) |
|---|--------|--------|
| \( E \) | \( EE \) | \( Ee \) |
| \( e \) | \( Ee \) | \( ee \) |

Result: Offspring genotypes are \( EE \), \( Ee \), \( Ee \), \( ee \).

#### Square 5:
Parents: \( A \) and \( a \)
- Top row: \( A \), \( a \)
- Left column: \( A \), \( a \)

| | \( A \) | \( a \) |
|---|--------|--------|
| \( A \) | \( AA \) | \( Aa \) |
| \( a \) | \( Aa \) | \( aa \) |

Result: Offspring genotypes are \( AA \), \( Aa \), \( Aa \), \( aa \).

#### Square 6:
Parents: \( D \) and \( d \)
- Top row: \( D \), \( d \)
- Left column: \( D \), \( d \)

| | \( D \) | \( d \) |
|---|--------|--------|
| \( D \) | \( DD \) | \( Dd \) |
| \( d \) | \( Dd \) | \( dd \) |

Result: Offspring genotypes are \( DD \), \( Dd \), \( Dd \), \( dd \).

#### Square 7:
Parents: \( H \) and \( h \)
- Top row: \( H \), \( h \)
- Left column: \( H \), \( h \)

| | \( H \) | \( h \) |
|---|--------|--------|
| \( H \) | \( HH \) | \( Hh \) |
| \( h \) | \( Hh \) | \( hh \) |

Result: Offspring genotypes are \( HH \), \( Hh \), \( Hh \), \( hh \).

#### Square 8:
Parents: \( N \) and \( n \)
- Top row: \( N \), \( n \)
- Left column: \( N \), \( n \)

| | \( N \) | \( n \) |
|---|--------|--------|
| \( N \) | \( NN \) | \( Nn \) |
| \( n \) | \( Nn \) | \( nn \) |

Result: Offspring genotypes are \( NN \), \( Nn \), \( Nn \), \( nn \).

#### Square 9:
Parents: \( Ee \) and \( Ee \)
- Top row: \( E \), \( e \)
- Left column: \( E \), \( e \)

| | \( E \) | \( e \) |
|---|--------|--------|
| \( E \) | \( EE \) | \( Ee \) |
| \( e \) | \( Ee \) | \( ee \) |

Result: Offspring genotypes are \( EE \), \( Ee \), \( Ee \), \( ee \).

#### Square 10:
Parents: \( Rr \) and \( rr \)
- Top row: \( R \), \( r \)
- Left column: \( r \), \( r \)

| | \( R \) | \( r \) |
|---|--------|--------|
| \( r \) | \( Rr \) | \( rr \) |
| \( r \) | \( Rr \) | \( rr \) |

Result: Offspring genotypes are \( Rr \), \( rr \), \( Rr \), \( rr \).

#### Square 11:
Parents: \( FF \) and \( Ff \)
- Top row: \( F \), \( f \)
- Left column: \( F \), \( F \)

| | \( F \) | \( f \) |
|---|--------|--------|
| \( F \) | \( FF \) | \( Ff \) |
| \( F \) | \( FF \) | \( Ff \) |

Result: Offspring genotypes are \( FF \), \( Ff \), \( FF \), \( Ff \).

#### Square 12:
Parents: \( BB \) and \( Bb \)
- Top row: \( B \), \( b \)
- Left column: \( B \), \( B \)

| | \( B \) | \( b \) |
|---|--------|--------|
| \( B \) | \( BB \) | \( Bb \) |
| \( B \) | \( BB \) | \( Bb \) |

Result: Offspring genotypes are \( BB \), \( Bb \), \( BB \), \( Bb \).

#### Square 13:
Parents: \( Nn \) and \( Nn \)
- Top row: \( N \), \( n \)
- Left column: \( N \), \( n \)

| | \( N \) | \( n \) |
|---|--------|--------|
| \( N \) | \( NN \) | \( Nn \) |
| \( n \) | \( Nn \) | \( nn \) |

Result: Offspring genotypes are \( NN \), \( Nn \), \( Nn \), \( nn \).

#### Square 14:
Parents: \( Dd \) and \( Dd \)
- Top row: \( D \), \( d \)
- Left column: \( D \), \( d \)

| | \( D \) | \( d \) |
|---|--------|--------|
| \( D \) | \( DD \) | \( Dd \) |
| \( d \) | \( Dd \) | \( dd \) |

Result: Offspring genotypes are \( DD \), \( Dd \), \( Dd \), \( dd \).

#### Square 15:
Parents: \( Ee \) and \( Ee \)
- Top row: \( E \), \( e \)
- Left column: \( E \), \( e \)

| | \( E \) | \( e \) |
|---|--------|--------|
| \( E \) | \( EE \) | \( Ee \) |
| \( e \) | \( Ee \) | \( ee \) |

Result: Offspring genotypes are \( EE \), \( Ee \), \( Ee \), \( ee \).

#### Square 16:
Parents: \( Bb \) and \( Bb \)
- Top row: \( B \), \( b \)
- Left column: \( B \), \( b \)

| | \( B \) | \( b \) |
|---|--------|--------|
| \( B \) | \( BB \) | \( Bb \) |
| \( b \) | \( Bb \) | \( bb \) |

Result: Offspring genotypes are \( BB \), \( Bb \), \( Bb \), \( bb \).

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Final Answer:

\[
\boxed{
\text{See detailed solutions above for each Punnett square.}
}
\]