Question

What is Recombinant DNA? Explain the process of separation and isolation of DNA using gel electrophoresis?

Answer 1

Hint: Genetic engineering, also known as recombinant DNA technology, includes a set of technologies for cutting and combining genetic material, especially DNA of different species, and injecting the resulting hybrid DNA into organisms to create new combinations of genetic genes. Gel electrophoresis is a method by which DNA fragments can be separated based on their size and charge.

Complete answer:
Part (i) A Recombinant DNA is a DNA molecule which has been prepared artificially by mixing the DNA fragments of two different organisms. It is prepared through recombination processes.
A recombinant DNA is a hybrid DNA consisting of genetic information in the form of genes from two or more organisms.
Part (ii) DNA is a negatively charged molecule and therefore moves towards anode, the positively charged electrode and hence it can be separated and isolated through agarose gel electrophoresis.
Steps of electrophoresis of DNA
Sample preparation – The DNA sample is treated with restriction endonuclease to break into smaller fragments.
Preparation of gel and its casting – agarose gel is prepared by casting \[1\% \] agarose in the electrophoresis chamber called gel casting. Ethidium bromide dye is also mixed during this step. Wells are prepared for sample loading.
Adding sample – The sample is loaded with the help of a micropipette.
Running the gel by passing the electric current through the electrodes in the electrophoretic chamber.
Visualization – DNA fragments are viewed as bands when viewed under UV through a UV transilluminator.
The separation of DNA fragments occurs based on their size and molecular weight.
The desired DNA band on the agarose gel is cut with the help of a scalpel blade and the DNA is extracted from this gel piece using various methods. Using DEAE cellulose membrane electrophoresis to extract DNA from agarose gels is one of the fastest and most effective methods.
Similarly, in an electroelution process, the gel fragments of the desired DNA bands are placed in a dialysis bag filled with buffer. The bag is then placed in a gel box containing a buffer and exposed to electric current. The extracted DNA precipitates out of the solution.
The method of extraction using DEAE cellulose membrane is to insert a piece of gel into a slot in DEAE cellulose paper, bind the DNA together, and then pass the band through the paper with an electric current. Wash the DNA from the paper and precipitate with ethanol.

Note:
Gel electrophoresis is a technique used in recombinant DNA technology to separate DNA fragments based on their size. In recombinant DNA technology, separated DNA fragments can be separated and analyzed by this method. Recombinant DNA technology is used to add desirable traits in many organisms. Organisms having recombinant DNA are called transgenic.