Question

Name and describe the technique that helps in separating the DNA fragments formed by the use of restriction endonuclease.

Answer 1

The technique used for separating DNA fragments in the lab is gel electrophoresis.

1. Electrophoresis enables to distinguish DNA fragments of different lengths.
   
2. DNA is negatively charged, therefore, when an electric current is applied to the gel, DNA will migrate towards the positively charged electrode. Shorter strands of DNA move more quickly through the gel than longer strands resulting in the fragments being arranged in order of size.
   
3. The use of dyes or radioactive labels enables the DNA on the gel to be seen after they have been separated. They will appear as bands on the gel.
   
4. A DNA marker with fragments of known lengths is usually run through the gel at the same time as the samples. By comparing the bands of the DNA samples with those from the DNA marker, one can work out the approximate length of the DNA fragments in the samples.