Question

Given below are the processes involved in recombinant DNA technology, which is used in the production of transgenic organisms:
1.Cutting of DNA at specific points to obtain the gene of interest
2.Isolation of DNA from the cellular components
3.Amplification of gene of interest
4.Inserting rDNA into the competent host cell
5.Inserting the gene of interest into a cloning vector
6.Separation of the isolated DNA fragments using agarose gel electrophoresis
From the options given below, choose the one which represents the correct order of these processes:

• A. 1→3→2→5→6→4
  
• B. 2→6→1→3→5→4
  
• C. 3→4→2→6→1→5
  
• D. 4→5→3→2→1→6
  

Answer 1

The correct option is B 2→6→1→3→5→4


Recombinant DNA technology is the technique of producing recombinant DNA by combining the DNA sequences from two different organisms.

Organisms that are genetically modified by inserting the recombinant DNA are called transgenic organisms.

The correct sequence of the processes involved in recombinant DNA technology, used in the production of transgenic organisms, is:
1.Extraction of genomic DNA by dissolving the cell wall and cell membrane of the cell from which gene of interest is to be isolated. The extract is then treated with proteases and ribonucleases to digest the proteins and RNA respectively. This is followed by precipitation of the purified DNA using chilled ethanol.
2.Next step is to separate the isolated DNA fragments based on size, using Agarose gel electrophoresis. The DNA fragments and size markers are loaded onto the gel well and current is passed through the gel. The DNA being negatively charged, move towards the positive electrode during gel electrophoresis. The smaller the size of the molecule, the faster and farther it travels. This is how the fragments are separated.
3.Cutting of the separated DNA fragment at specific points using restriction enzymes to obtain the gene of interest.
4.Amplification of gene of interest using PCR.
5.Inserting the gene of interest into a cloning vector. This is done by cutting the cloning vector with the same restriction enzyme that was used to cut out the gene of interest. Now that the gene of interest and the cloning vector have complementary open ends, they can be joined together using the ligase enzyme.
6.Inserting rDNA into the competent host cell by using techniques such as chemical transformation, electroporation, etc.