Offsprings of which cross will be phenotypically & genotypically similar -

Options

A. Dd `×x` Dd
B. DD `×x` dd
C. DD `xx` Dd
D. Ww `×x` Ww

Answer

To determine which cross will produce offspring that are phenotypically and genotypically similar, we need to analyze the given options based on Mendelian genetics principles.

### Step-by-Step Solution:

1. **Understand the Definitions**:
- **Phenotype**: The observable traits of an organism (e.g., color, shape).
- **Genotype**: The genetic makeup of an organism (e.g., alleles present).

2. **Analyze the Options**:
- **Option 1**: Cross between **Dd x Dd** (heterozygous x heterozygous).
- Possible offspring: DD, Dd, Dd, dd.
- Phenotypic ratio: 3 dominant: 1 recessive.
- Genotypic ratio: 1 DD: 2 Dd: 1 dd.
- **Conclusion**: Not similar.

- **Option 2**: Cross between **DD x dd** (homozygous dominant x homozygous recessive).
- Possible offspring: All Dd.
- Phenotypic ratio: All dominant.
- Genotypic ratio: All Dd.
- **Conclusion**: Both phenotype and genotype are similar.

- **Option 3**: Cross between **DD x Dd** (homozygous dominant x heterozygous).
- Possible offspring: DD, DD, Dd, Dd.
- Phenotypic ratio: 2 dominant: 0 recessive.
- Genotypic ratio: 2 DD: 2 Dd.
- **Conclusion**: Not similar.

- **Option 4**: Cross between **Ww x Ww** (heterozygous x heterozygous).
- Possible offspring: WW, Ww, Ww, ww.
- Phenotypic ratio: 3 dominant: 1 recessive.
- Genotypic ratio: 1 WW: 2 Ww: 1 ww.
- **Conclusion**: Not similar.

3. **Final Conclusion**:
- The only cross that produces offspring that are both phenotypically and genotypically similar is **Option 2: DD x dd**.