iv.1. Recombinant DNA technology: Definition

delete UPSC Sample Notes [English]

iv.1. Recombinant DNA technology: Definition

Recombinant DNA technology comprises altering genetic material outside an organism to obtain enhanced and desired characteristics in living organisms or as their products.

This technology involves the insertion of DNA fragments from a variety of sources, having a desirable gene sequence via appropriate vector.

Recombinant DNA Technology

A method primarily used to alter the phenotypic of an organism (host) after introducing and integrating a genetically changed vector into the organism’s genome.
Therefore, in essence, this technique entails inserting an unfamiliar piece of DNA structure into the genome that houses our target gene.
This injected gene is a recombinant gene, and the process is known as recombinant DNA technology.
Recombinant DNA technology uses a number of techniques, equipment, and other particular procedures to produce artificial DNA in order to create the desired result.
Recombinant DNA Technology is the name given to the process of creating artificial DNA by fusing DNA from various sources with various genetic components. Genetic engineering is the term used to refer to recombinant DNA technologies.
In 1968, Swiss microbiologist Werner Arber made the discovery of restriction enzymes, which led to the development of the recombinant DNA technology.
It’s harder than it sounds to splice the desired gene into the host’s genome. It entails choosing the ideal vector with which to integrate the intended gene and create recombinant DNA after choosing the appropriate gene to be administered into the host.
As a result, the host must be given the recombinant DNA. Finally, it needs to be kept alive in the host and passed on to the progeny.
Recombinant DNA multiplies and is expressed in the form of the created protein under ideal conditions following insertion into the host cell.
The recombinant gene is passed down to the progeny by the successfully transformed cells or organisms.
Science, medicine, agriculture, and industry can benefit from the unique genetic combinations that the recombinant DNA molecule creates.
Two findings made while dealing with bacteria gave rise to recombinant DNA technology: the existence of plasmids or additional chromosomal DNA pieces that can carry foreign DNA and proliferate alongside bacterial DNA in a bacterial cell.
Availability of particular restriction enzymes that attack and cleave DNA at particular places.
A lot of agriculture uses recombinant DNA technologies to create genetically engineered species.
It is employed in the manufacturing of medications like insulin.

Tools Of Recombinant DNA Technology

Restrictions enzymes, polymerases, and ligases are among the enzymes that aid in cutting, synthesis, and binding. The position at which the desired gene is inserted into the vector genome is greatly influenced by the restriction enzymes utilised in recombinant DNA technology. Endonucleases and exonucleases are the two types.

Endonucleases and Exonucleases:

The exonucleases remove the nucleotides off the ends of the strands, whereas the endonucleases cut within the DNA strand. The restriction endonucleases are sequence-specific and cut the DNA at predetermined locations. These sequences are typically palindrome sequences. They check the DNA’s length and make the cut at a certain location known as the restriction site.

In the sequence, this results in sticky ends. The same restriction enzymes are used to cut both the vectors and the desired genes, resulting in complementary sticky notes. This makes it simple for the ligases to link the desired gene to the vector.

The vectors:

The required gene may be carried by and integrated into the vectors. They are a crucial component of the recombinant DNA technology’s tools since they are the ultimate carriers of the desired gene into the host organism. The most popular vectors employed in recombinant DNA technology are bacteriophages and plasmids because of their high copy numbers.

The components of the vectors are the origin of replication, which is a sequence of nucleotides from which the replication begins, a selectable marker, which are genes that exhibit resistance to specific antibiotics like ampicillin, and cloning sites, which are the locations where desired DNAs are inserted and are recognised by restriction enzymes.

Host organism:

The organism that serves as the host for the recombinant DNA. The host, which accepts the vector created with the required DNA with the aid of enzymes, is the ultimate tool of recombinant DNA technology.

Process involved in Recombinant DNA Technology

These recombinant DNAs can be introduced into the host in a variety of ways, including microinjection, biolistics or gene gun, alternate cooling and heating, usage of calcium ions, etc.

Recombinant DNA technology involves a number of stages kept in a particular order to produce the desired output.

Step-1 Isolation of Genetic Material.

Isolating the desired DNA in its pure state, that is, free of extraneous macromolecules, is the first and most important step in the recombinant DNA technology process.

Step-2 Cutting the gene at the recognition sites.

The restriction enzymes are important in deciding where to introduce the desired gene into the vector genome.
Restrictions enzyme digestions are the name given to these processes.

Step-3 Amplifying the gene copies through Polymerase chain reaction (PCR).

Once the correct gene of interest has been cut using restriction enzymes, a procedure called DNA amplification is used to multiply a single copy of DNA into thousands to millions of copies.

Step-4 Ligation of DNA Molecules.

With the aid of the enzyme DNA ligase, the two pieces—a cut fragment of DNA and the vector—are joined at this stage of ligation.

Step-5 Insertion of Recombinant DNA Into Host.

The recombinant DNA is now inserted into a recipient host cell in this stage. Metamorphosis is the name given to this process.
Once the recombinant DNA has been put into the host cell, it multiplies and, under ideal circumstances, expresses itself as the produced protein.

There are several ways to accomplish this, as was discussed in Tools of recombinant DNA technology. The recombinant gene is passed down to the progeny by the successfully transformed cells or organisms.