The sample is immediately placed in a preservative solution. The Zoogen instructions tell you to use rubbing alcohol, 70- ethanol, gin or vodka in case you lose the preservative provided by them. In my Biology II class, I ran DNA isolations on calf liver. At Zoogen, solutions are added to the sample. They are shaken and centrifuged to separate the solution into several layers.
Heavier particles go to the bottom and lighter particles rise to the surface.
The DNA can be removed at this point and is a very thick, sticky small mass. This step could take about a day to complete. More isolation procedures are run to further dissolve the DNA which could take another 10 hours. The isolated DNA is next dissolved in another solution containing enzymes called restriction enzymes. They work to cut up foreign DNA restricting it from surviving in your own cells.