What is a gene library ?

Options

A. Information stoted for DNA sequence
B. DNA fragments in agarose gel
C. Photographs of DNA fragements
D. DNA fragments of a genome maintained by cloning in culture cells

Answer

### Step-by-Step Solution:

1. **Definition of Gene Library**:
- A gene library is a collection of DNA fragments from an organism that have been cloned into vectors for storage and purification.

2. **Purpose of a Gene Library**:
- The primary purpose of a gene library is to preserve and study the genetic material of an organism. It allows researchers to access specific DNA sequences for various applications, such as gene cloning, sequencing, and functional studies.

3. **Types of Gene Libraries**:
- There are two main types of gene libraries:
- **Genomic Library**:
- This library contains DNA fragments that represent the entire genome of an organism.
- The process involves extracting DNA from cells, cutting it into fragments using restriction enzymes, and then ligating these fragments into vectors. The vectors are then introduced into bacterial cells for cloning.
- **cDNA Library**:
- This library is made from complementary DNA (cDNA) synthesized from messenger RNA (mRNA).
- The process involves reverse transcription of mRNA to produce cDNA, which is then cut into fragments and cloned into vectors, similar to the genomic library process.

4. **Cloning Process**:
- Cloning involves inserting DNA fragments into vectors (like plasmids) that can replicate within host cells (usually bacteria). This allows for the amplification of the DNA fragments, making it easier to study and manipulate them.

5. **Applications of Gene Libraries**:
- Gene libraries are used in various fields, including biotechnology, medicine, and research. They facilitate the identification of genes, the study of gene function, and the production of recombinant proteins.