Definition of Recombinant DNA (rDNA)

Definition of Recombinant DNA (rDNA)

“The recombinant DNA abbreviated as rDNA is an artificial DNA molecule manufactured using two different DNAs and used to produce recombinant protein, treat disease and produce genetically engineered organisms.” 


Can we join two DNA, artificially? Can we express it in an organism and can we tailor a lab-made living thing having a different genetic combination? The answer is yes! In modern days but it might a ‘daydream’ in the 50s.  

Scientists know about DNA, genes and chromosomes since the 18th century, the experiments of Mendel are proofs. But the actual structure was not known and therefore, most areas of genetics remained in mystery until the 1950s. 

In 1953, two researchers- J Watson and F Crick have unfolded the structure of DNA and explained the molecular organization of DNA. That was the era doors for molecular genetics, genetic engineering, gene therapy and gene alterations were opened. 

Afterwar, enzymes like restriction endonucleases, ligases, helicase were discovered and other tools like PCR- polymerase chain reaction, DNA sequencing and Southern blot like technique came to light that had changed the field of genetic technology and processing of molecules.

The concept of rDNA or recombinant DNA was originated in this period as well when two Standford scientists have postulated the concept of recombinant DNA. 

rDNA- recombinant DNA has changed the entire field of genetics with infinite possibilities to change the genome of organisms and to produce beneficial genomesThe idea was like a fairytale until the 1960s but tools like restriction enzymes, ligases, polymerase, and helicase made it possible. 

The present article concentrate on the definition of recombinant DNA, what is it and what are its applications, We will also discuss the process and steps elaboratively and other aspects of the present technique. 

Definition of recombinant DNA-

To define recombinant DNA, we need to understand, first, what is it, the process and how the technique work. It’s not a ‘Himalayan task’, to define the rDNA though to learn the exact definition or in-depth explanation of the same, is very important for a genetic student or even for others too. 

So let’s start with what the rDNA or recombinant DNA is! 

What is recombinant DNA? 

In layman, recombinant DNA is two different DNA combined (artificially) for different purposes, conceptualized by Lobban and Dale, from Stanford University during 1970. 

In 1978, A Werner, N Daniel and S Hamilton had discovered restriction enzymes, however. They also have postulated the process of isolation and producing rRNA in the lab in the same paper and awarded the Nobel Prize in Medicine for the present discovery. 

Notably, discoveries of restriction enzyme and ligase provided the cutting edge sharpness and versatility to the technique. 

Conclusively, The trio- (Werner, Daniel and Hamilton) and P Berg, had awarded the Nobel prize of Physiological Medicines, and chemistry, respectively for their valuable contributions to the field of rDNA technology. 

Aims and objectives: 

As a scientist, the first question that arises in mind is, “why to join or combine two genes or DNA?” The technique of recombinant DNA produces an altered gene or DNA made up of two different nucleotide sequences. The objectives are;

  • To produce an altered DNA
  • To edit gene and overcome mutation
  • To produce GMOs- genetically modified organisms 
  • To produce economically essential species 
  • To produce useful microbes 
  • To produce recombinant proteins 
  • To produce unique gene 
  • To treat genetic disease 

Originally the technique of rDNA was evolved to produce recombinant proteins. Insulin was the first protein produced through recombinant DNA technology in which a gene for human insulin was isolated inserted into a microorganism to produce protein insulin. 

Steps and procedure:

Don’t worry we haven’t forgotten to define recombinant DNA. To head towards the definition we need to understand the procedure. 

Step: 

  1. Selection of target organisms 
  2. Isolating a gene of interest 
  3. Selecting an expression vector 
  4. Recombining the target gene 
  5. Expression of a target gene into the host 
Production of therapeutic protein using the genetic engineering technique.
Production of therapeutic protein using the genetic engineering technique.

Procedure: 

The standard procedure of rDNA is similar much like other genetic engineering technique which starts with selecting the target organism as well as isolating the gene of interest. 

Afterward, the expert selects an expression vector to insert an altered gene, commonly the plasmid DNA. The plasmid is a circular single-stranded DNA commonly used as a vehicle to transfer the gene of interest. 

The restriction enzyme cuts the DNA and plasmid to produce sticky ends. The ligase seals the gap between the two and creates the unique circular plasmid having two different DNA or genes, viz gene of their own and our gene of interest. 

Soon after, plasmid expresses in the host organism and produces copies of rDNA, the alternative technique, known as polymerase chain reaction can also be used to produce copies of DNA in the lab. 

The gene of interest inserts into the host and expresses or produces the desired protein product we want. 

To tread disease, scientist inserts plasmid in live human cells, induces gene expression, and let them divide to replace the faulty gene with the newer recombinant one. 

Definition of recombinant DNA: 

Now come to our original point of discussion, what is the definition of recombinant DNA? Let’s combined the elements we have discussed so far, 

A laboratory tool used to join two different DNA segments or gene in order to created altered DNA and insert into the host organism is known as recombinant DNA. 

Or 

Combining and inserting two different genes or DNA segments in order to produce recombinant protein is known as recombinant DNA. 

Or 

A technique of genetic engineering to combining two different genes and inserting it in a host organism for various applications is known as recombinant DNA. 

Applications of recombinant DNA: 

Now let’s briefly explain several applications of the present technique.

  • To produce recombinant protein 
  • To replace the faulty or mutated gene in gene therapy for treating genetic disease. 
  • To produce economically important plant species. 
  • To produce abiotic and biotic stress resistant plant species. 
  • To produce GMO- plant, animal and microbe species 
  • To create novel gene variants. 

Conclusion: 

Conclusively, the technique of rDNA technology is one of the most growing technologies in science, however, there are several drawbacks and setbacks to it and people also don’t want some genetically altered products. But still, it has the potential to change many things in the world.

If you want to learn more rDAN technology, genetic engineering and gene transfer techniques you can read our previous article.

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