The process of extracting the DNA is a very complex, time taking and tedious task. It needs lots of technical knowledge in order to extract DNA.
There are various chemicals used during the process of DNA extraction. The use of isopropyl alcohol is to precipitate the DNA.
This precipitation makes the DNA visible as it is clumped together. Then it becomes easy for the long strands of DNA to wrap around the stirrer when swirled at the interface between two layers.
