Reference sources: 1  Petwave.com â Obesity Problems. 2  Petwave.com â Dogs Health. 3  Petwave.com â Cancer Types.  Dog Time.com â 10 Most Serious Pet Diseases.
Only a small sample of cells is needed for DNA fingerprinting. A drop of blood or the root of a hair contains enough DNA for testing. Semen, hair, or skin scrapings are often used in criminal investigations. A person who has DNA fingerprinting done voluntarily usually provides a sample of blood taken from a vein.
To get the DNA fingerprint: 1  All of the DNA is broken into pieces at certain locations. This is done by chemicals (enzymes) that break each DNA strand at the same place. 2  The DNA pieces are placed at the top of a special gel held in a frame. 3  An electric current is applied to the gel. The current separates the DNA into bands of identical pieces.