Which of the following vector is used extensively for genetic engineering in animals?

Options

A. E.coli
B. Ti plasmid
C. Bacillus thuriengenensis
D. Retrovirus (disarmed)

Answer

To answer the question "Which of the following vector is used extensively for genetic engineering in animals?", we will analyze each of the options provided:

1. **E. coli**:
- E. coli is a common bacterium that is widely used as a vector in genetic engineering. It possesses a small circular DNA called plasmid, which can be manipulated to carry foreign DNA. E. coli has an origin of replication, which allows it to replicate the inserted DNA. It also contains selectable markers, such as antibiotic resistance genes, which help in identifying successfully transformed cells. However, E. coli is primarily used in the cloning of genes and not directly in animal genetic engineering.

2. **T.I. plasmid**:
- The T.I. (Tumor Inducing) plasmid is derived from Agrobacterium tumefaciens and is primarily used in plant genetic engineering. This vector is not suitable for animal genetic engineering, as it is specifically designed to transfer genes into plant cells.

3. **Bacillus thuringiensis**:
- Bacillus thuringiensis (Bt) is a bacterium that produces toxins harmful to certain insects and is used as a biological pesticide in crops. It is not a vector for genetic engineering in animals, but rather a source of genes for pest resistance in plants.

4. **Retrovirus**:
- Retroviruses are RNA viruses that can integrate their genetic material into the host's DNA. They are indeed used in genetic engineering, particularly in animal cells, for gene therapy and the introduction of new genes into animal genomes. Retroviruses can effectively deliver genes into animal cells, making them a suitable vector for genetic engineering in animals.

Based on the analysis of the options, the most appropriate answer to the question is:

**Answer: Retrovirus**