How many types of zygotic combinations are possible between a cross Aa BB Cc Dd `xx` AA bb Cc DD ?

Options

A. 32
B. 128
C. 64
D. 16

Answer

To solve the question of how many types of zygotic combinations are possible between the cross Aa BB Cc Dd and AA bb Cc DD, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Genotypes of the Parents**:
- Parent 1: Aa BB Cc Dd
- Parent 2: AA bb Cc DD

2. **Determine the Number of Heterozygous Alleles**:
- For Parent 1 (Aa BB Cc Dd):
- Aa: 1 heterozygous allele (A/a)
- BB: 0 heterozygous alleles
- Cc: 1 heterozygous allele (C/c)
- Dd: 1 heterozygous allele (D/d)
- Total heterozygous alleles in Parent 1 = 1 + 0 + 1 + 1 = 3
- For Parent 2 (AA bb Cc DD):
- AA: 0 heterozygous alleles
- bb: 0 heterozygous alleles
- Cc: 1 heterozygous allele (C/c)
- DD: 0 heterozygous alleles
- Total heterozygous alleles in Parent 2 = 0 + 0 + 1 + 0 = 1

3. **Calculate the Number of Gametes**:
- The formula to calculate the number of gametes is \(2^n\), where \(n\) is the number of heterozygous alleles.
- For Parent 1: \(2^3 = 8\) gametes
- For Parent 2: \(2^1 = 2\) gametes

4. **Calculate the Number of Zygotic Combinations**:
- The total number of zygotic combinations is the product of the number of gametes from both parents.
- Total zygotic combinations = Number of gametes from Parent 1 × Number of gametes from Parent 2
- Total zygotic combinations = \(8 \times 2 = 16\)

5. **Conclusion**:
- The total number of zygotic combinations possible from the cross Aa BB Cc Dd and AA bb Cc DD is **16**.

### Final Answer:
The number of zygotic combinations possible is **16**.

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