How can DNA be extracted from saliva?
Answers
DNA in Saliva. The DNA in saliva originates from cells that are shed from the inner linings of the mouth and from white blood cells. These DNA-containing cells are collected, and the DNA is then extracted by various methods.
Step 1: Break cells open.
There are actually a few methods to accomplish this. One even uses soap!
The membranes of cells are made up of lipids (also know as fats). As it turns out, soaps are really good at breaking up and dissolving fats. Therefore, when you mix the soap with the cells, it basically breaks up and dissolves away the membrane of the cell, thus causing the DNA to float right on out. The soap doesn’t mess with the DNA because the DNA isn’t made of lipids.
Step 2: Separate DNA from other parts of the cell such as proteins.
Step 3: Precipitate (purify) the pure DNA from everything else
Finally, using a chemical (typically ethanol), we clump DNA together to make it form a solid. This solid is then removed from the solution. We call this process precipitation.