The process of carrying out a DNA test

Deoxyribonucleic acid, other wise known as DNA, forms the genetic blueprint for every living organism on the planet. In a sense, one human being is indistinguishable from another in terms of DNA similarity; however there are a few minor exceptions which mean that some humans are more similar to others as they are connected as families or “blood relations”. To explain: 99.9% of human DNA sequences are the same in each individual, however there is enough DNA to be able to differentiate one person from another. In DNA testing, repeat or repetitive sequences are used which are highly variable, known as variable number tandem repeats or VNTR –loci which are highly similar between two persons related to one another –so similar that unrelated humans are very unlikely to have the same variable number tandem repeats as the relations.
It is this form of DNA which is often used for DNA testing, which has a number of different applications. The process of carrying out a DNA testor DNA profiling as it is also known was first described by Sir Alec Jeffreys for the University of Leicester. It now forms the basis for many national DNA databases. Jeffreys also pioneered the genetic fingerprinting technique, which was made commercially available at chemical company ICI in 1987 when the company opened a centre for blood testing.
Genealogy is a common form of DNA test which has recently been popularised by the current trend for tracing a person’s origins through birth, death and marriage records online. However, this method of tracing one’s ancestry can be fairly limited due to records running out or missing altogether, and as a result many are turning to DNA tests in order to trace their genetic lineage.
DNA testing is also used to determine more recent family ties, for example in paternity and maternity testing. This form of DNA test normally involves a buccal swab taken of each subject prior to being taken to the lab to be compared and contrasted. These DNA tests are also used for other family methods and also for twin or zygosity testing.
Samples for DNA tests can be taken from anywhere on the human body. Common samples which are used include blood samples, saliva, skin cells, hair and sperm samples. These are often collected at crime scenes to provide legal evidence, as are fingerprints, which are directly related to the individual makeup of a person’s DNA. There has been some speculation as to whether a criminal would be able to plant “fake” DNA at the scene of a crime (Which has previously been attempted), but according to scientists, in order for this to be able to cover a criminal’s tracks sufficiently, they would need a wealth of laboratory equipment and a lab technician or engineer on hand.