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 concepts of phenotype and genotype in the context of Mendelian genetics.

### Step-by-Step Solution:

1. **Understanding Phenotype and Genotype**:
- **Phenotype** refers to the observable traits or characteristics of an organism, such as color, shape, or size.
- **Genotype** refers to the genetic makeup of an organism, which includes the alleles (dominant or recessive) that an organism carries.

2. **Identifying Conditions for Similarity**:
- For offspring to be both phenotypically and genotypically similar, they must inherit the same alleles from their parents. This typically occurs in specific types of genetic crosses.

3. **Monohybrid Cross**:
- A **monohybrid cross** involves a single trait and typically involves one dominant and one recessive allele. For example, crossing a homozygous dominant (DD) with a homozygous recessive (dd) will yield offspring that are all heterozygous (Dd), which will express the dominant phenotype.

4. **Homozygous vs. Heterozygous**:
- If both parents are homozygous (either both dominant or both recessive), all offspring will be genetically identical (homozygous) and will express the same phenotype.
- If one parent is homozygous dominant (DD) and the other is homozygous recessive (dd), all offspring will be heterozygous (Dd) and will show the dominant phenotype.

5. **Choosing the Correct Cross**:
- Among the given options, the cross that results in offspring being both phenotypically and genotypically similar must involve either:
- Two homozygous parents (DD x DD or dd x dd)
- A monohybrid cross where one parent is homozygous and the other is homozygous recessive (DD x dd).

6. **Conclusion**:
- Based on the analysis, the correct answer would be the cross that involves homozygous alleles (e.g., DD x DD or dd x dd), as these will produce offspring that are identical in both phenotype and genotype.