Recombinant DNA Technology

Recombinant DNA (rDNA) technology is the process of generating artificial DNA molecules by combining DNA fragments from two different species. This technology enables the rearrangement of genetic material to allow specific genes to be replicated or expressed in particular cells.

History

The fundamental principles of genetic recombination were first described by Frederick Griffith in 1928, and this process was termed “genetic transformation.” The foundations of recombinant DNA technology were laid in 1973 by Stanley Cohen and Annie Chang through in vitro plasmid production.

Technological Structure and Components

Recombinant DNA consists of two main components: a vector plasmid and a DNA fragment containing the target gene. Plasmids are circular double-stranded DNA molecules found in bacteria yeasts and some eukaryotic organisms that are separate from chromosomal DNA. Through genetic engineering these plasmids are modified to function as carrier vectors.

Vectors are classified into different subtypes based on the elements they contain:

Cloning Plasmids:

Used for amplifying specific DNA regions.

Shuttle Vectors:

Designed to function in more than one cell species.

Expression Vectors:

Used to ensure the expression of a specific gene.

Gene Knockdown Vectors:

Used to reduce the expression of a specific gene.

Reporter Plasmids:

Used to study the expression of other genes.

Viral Plasmids:

Used for viral capsid production and targeting studies.

All vectors contain as essential structural elements: common antibiotic resistance genes an origin of replication and a multiple cloning site like. Some vectors also include promoter regions primer binding sites and selectable markers place.

Stages of Recombinant DNA Technology (created by YZ)

Application Methods

The transfer of recombinant DNA into cells occurs through three primary methods:

Transformation: Transfer into bacterial cells.

Transfection: Transfer into eukaryotic cells.

Transduction: Gene transfer via Virus.

Cells resulting from these procedures are called transgenic cells. These cells can replicate express or exhibit other genetic properties depending on the structure of the associated vector.

Applications

Recombinant DNA technology has broad applications in medical research and product development. Human insulin was first expressed using this technology in the bacterium Escherichia coli between 1978 and 1981. In 1981 its interaction with human receptors was demonstrated and clinical use began in 1982.

It has also been used in vaccine development. For example the first recombinant vaccine for Hepatitis B virus was produced in 1986 using the HBsAg gene in the yeast Saccharomyces cerevisiae. Additionally in 1998 recombinant human serum albumin was first produced in the yeast Pichia pastoris and clinically tested.

This technology is also employed in basic scientific research. In a 2015 study the human insulin-like growth factor binding proteins was expressed in the HEK293 cell line to perform functional analysis of these proteins.

Recombinant DNA technology is a comprehensive set of methods used for various functions in both applied and fundamental molecular biology research. By enabling the artificial manipulation of genetic material it plays a critical role in the development of numerous products.