Question

What is elution in the process of separation of DNA fragments?

Answer 1

Break down of DNA molecule into DNA fragments is done with the help of enzyme restriction endonuclease. These fragmented DNA can be separated or isolated using techniques like gel electrophoresis.

Complete answer: Cutting DNA into fragments is one of the important steps in genetic engineering and many more. These fragments are to be separated and for that gel, electrophoresis technique is used.
In-gel electrophoresis, the fragments of DNA are separated based on their size and the charge on them. A gel (agarose which is a natural polymer) matrix containing the DNA molecule is subjected to an electric current that forces the DNA molecule to move towards an anode (i.e. positive end) as DNA is a negatively charged molecule. Now based on the size of DNA, separation will occur i.e. DNA fragments with smaller sizes will move faster compared to the ones with the larger sizes. These separated fragments are not visible to bare eyes hence they are observed under UV radiation. The DNA fragments need to be dyed using ethidium bromide which gives us separate bands on the agarose gel. This gel is then observed under UV light to see a separate DNA band.
The separated bands on agarose gel are then cut out along with gel and DNA is isolated from this gel piece. The process of extraction of DNA from this agarose piece is known as elution in electrophoresis.

Note: Gel electrophoresis can be used to perform separation of RNA as well. The elution process i.e. recovery of DNA from the agarose gel after electrophoretic separation is also known as a gel purification process.