What is recombinant DNA?

Options

A. DNA in which RNA is integrated
B. DNA which is obtained by transcription of RNA
C. DNA which is inserted into a newly reconstructed cell
D. DNA which contains alien genes i.e. genes from more than one source organism

Answer

**Step-by-Step Solution:**

1. **Definition of Recombinant DNA:**
- Recombinant DNA refers to a form of DNA that has been artificially created by combining genetic material from two or more different sources. This process results in a new sequence of DNA that contains genes from multiple organisms.

2. **Process of Creating Recombinant DNA:**
- The creation of recombinant DNA typically involves the following steps:
- **Selection of Gene of Interest:** Identify and isolate the gene that you want to insert into another organism's DNA.
- **Use of Plasmids:** A plasmid, which is a small circular DNA molecule found in bacteria, is often used as a vector to carry the gene of interest.
- **Cutting the DNA:** Restriction enzymes, also known as restriction endonucleases, are used to cut the plasmid DNA at specific sites. This creates openings where the gene of interest can be inserted.
- **Ligation:** The gene of interest is then inserted into the cut plasmid. DNA ligase, an enzyme, is used to join the ends of the plasmid DNA and the gene of interest, forming a stable recombinant DNA molecule.

3. **Characteristics of Recombinant DNA:**
- The resulting recombinant DNA contains genetic information from different sources, which is why it is referred to as containing "alien genes" or foreign genes. This allows for the expression of new traits or characteristics in the host organism.

4. **Correct Answer:**
- Among the given options, the correct definition of recombinant DNA is: "DNA which contains alien genes i.e., genes from more than one source of organisms." This option accurately reflects the nature of recombinant DNA.