A more detailed explanation of the process of DNA profiling - by Dr Jeff Sampson.

Buried within the DNA of each and every individual is a special DNA signature that can be used to uniquely identify that individual. DNA profiling is the name given to the technique that has been developed to reveal this DNA signature. Initially, DNA-based approaches to identifying individuals were pioneered in humans, but the same technology has easily been transposed to the dog. Nowadays, special sequences found in DNA called microsatellites are used to build up this DNA signature. Microsatellites have become the system of choice for DNA profiling and genetic testing in humans. The US Armed Forces, FBI, Scotland Yard, The Royal Canadian Mounted Police and multiple forensic laboratories use microsatellites for their forensic, paternity and individual identification tests. The reasons that have made them come to the fore in humans are the very reasons that currently make them the system of choice for dogs.

The technique essentially involves preparing a DNA sample from an individual dog. For this we need to obtain some tissue from the dog in order to prepare the DNA. The ideal source of material would be a blood sample which will permit us to isolate DNA from the white cells; this however requires a vet to take the sample of blood before passing it onto the laboratory for testing. Less invasive techniques which don't require veterinary intervention have therefore been sought to make the procedure more convenient. One alternative source of tissue are the cells that can be easily removed from the inside of a dog's cheek, called buccal cells.

In this case all that is required is to gently rub a small plastic brush against the inside of the cheek to remove the buccal cells. The brush, containing the cells can then be returned to the laboratory for analysis. DNA can be made from both tissue sources, although considerably less DNA is provided by the buccal cells because they are considerably fewer in number.

Once isolated, the DNA can then be treated to reveal the individual-specific DNA signature. Several laboratories throughout the world have been using this technique successfully for a number of years. Many of you will have read in the dog press of the American Kennel Club's pilot study on DNA profiling which has recently been concluded.

What can DNA profiling offer? Well, as I have explained, the DNA signature that is revealed can uniquely identify an individual dog. However, the profile is not just a means of identification because it also carries within it information on the parents of the dog. This is because a puppy inherits half of its DNA from its mother and the remaining half from its father. This essentially means that half of the components that make up the profile are maternal in origin and the other half paternal. So it is in these two areas that profiling has impact: individual identification and parentage verification.

Kennel Club Information Guide - DNA Profiling and Parentage Analysis