DNA is the short form for Deoxyribonucleic acid. This is an acid present in the cells of human beings. Within this, one can find the genetic information for that individual. Genetic information governs many different aspects of an individual's life. A person's physical appearance is a result of his or her DNA structure. This DNA is received from both parents in equal halves. This is why one would see that members of a family tend to look alike with some variations. This is also the reason why identical twins are so alike, as they share the same genetic structure with each other.
A DNA test requires a sample from the individual that is undergoing testing. This sample of DNA evidence can be collected from various body fluids of the individual including blood, semen and saliva. DNA evidence could also be collected from tissue or hair samples of an individual. The most popular method of DNA evidence collection is using a buccal swab. This is a relatively contaminant free procedure which allows the testing to be fairly accurate.
The DNA testing procedure for the patient is very simple. The patient simply has to have a sample collected and sent to an accredited laboratory. When the testing is being done anonymously, the sample may be collected by the individual at home and sent to the laboratory by mail. For home testing, the sample is usually saliva collected on a cotton swab, the swab being supplied by the laboratory conducting the test. In all other cases, the laboratory will collect the sample from the patient.
DNA evidence is then analyzed using one of the many available testing procedures. These DNA testing procedures use the collected evidence to determine various genetic markers. These markers are useful when comparing DNA from a particular individual with DNA from another individual. This is done to establish the presence or absence of a match between these two individuals. When the DNA test is being used to establish whether an individual is susceptible to a disease or condition, the concerned genes associated with that disease are studied carefully to check for indications of an inherited susceptibility.
For cases involving crimes, a DNA test may be used on a suspect to link him or her to a crime scene from which DNA evidence has been collected. The suspect may be made to give some DNA material to prove or disprove innocence in the matter.