Transformation is due to

Options

A. Transfer of chimeric DNA into host cell
B. Synthesis of C DNA from RNA
C. Synthesis of Polypeptide chain from mRNA
D. Insertion of gene into suitable vector

Answer

**Step-by-Step Text Solution:**

1. **Understanding Transformation**: Transformation refers to the process by which a cell takes up foreign DNA and incorporates it into its own genome, leading to a change in its characteristics. This is a key concept in molecular biology and genetic engineering.

2. **Analyzing the Options**: The question provides four options regarding what causes transformation. We need to evaluate each option to determine which one correctly describes the process of transformation.

3. **Option A - Transfer of Chimeric DNA into Host Cell**: This option suggests that transformation occurs when chimeric DNA (a DNA molecule made from two different sources) is transferred into a host cell. This is indeed the correct mechanism of transformation, as the introduction of foreign DNA into a host cell is what causes the genetic alteration.

4. **Option B - Synthesis of cDNA from RNA**: This option refers to the process of reverse transcription, where complementary DNA (cDNA) is synthesized from an RNA template. While this is an important process in molecular biology, it does not directly relate to transformation.

5. **Option C - Synthesis of Polypeptide Chain from mRNA**: This option describes translation, the process by which ribosomes synthesize proteins based on the sequence of mRNA. This process is not related to transformation, as it does not involve the uptake of foreign DNA.

6. **Option D - Insertion of Gene into Suitable Vector**: This option refers to the process of cloning where a gene is inserted into a vector for propagation. While this is a crucial step in genetic engineering, it does not directly cause transformation in the context of a host cell taking up DNA.

7. **Conclusion**: After analyzing all the options, we conclude that the correct answer is **Option A: Transfer of chimeric DNA into host cell**, as this is the process that leads to transformation.