Although the vast majority of DNA in people is the same from one person to the next, there is a small portion that differs in every individual. A DNA test compares fragments, called genetic loci, from this pool of DNA in order to determine whether there is a likelihood that two DNA samples are similar enough that their donors are related. A child inherits 50% of his DNA from one parent and 50% from the other so by testing enough loci it is possible to accurately determine whether enough loci are shared to consider the two to be a match.
DNA is not only present in all people but they are the molecules that determine everything about that person. The colour of your hair, shade of your skin, and even whether you are a naturally happy person are all determined by your DNA. Its importance and relevance means that it has fascinated scientists for many years and while there is still much we can learn from it, there is also a lot that we have already learned. We certainly have a good understanding of the basic workings of DNA.
When a baby is borne they will have 50% of their DNA from their father and 50% from their mother. However, despite 3 billion DNA code sequences in the human body, around 99.9% of these are the same in every single person. The remaining code markers are what make us unique from one person to the next and it is this pool of DNA that is tested when a DNA test is undertaken.
Identical twins have identical DNA markers but nobody else in the world will share your precise DNA code. This makes it unique and it us why DNA testing is used in forensics to help catch criminals. The relationship between parents and children, siblings and other relatives, and the mixture of DNA in their body is what makes testing useful as a means of parental testing. Paternity tests are the most common but there are also viable reasons to carry out maternity tests as well.
A single cell belonging to the body contains all of the DNA related to that body. This means that it is not necessary to take blood or extract marrow in order to acquire DNA. A hair or some saliva will usually provide adequate results. With a home test you will usually be required to take a swab from the inside of your mouth from you and the other person being tested. The two resulting DNA samples are then broken down so that the unique areas of DNA can be tested for matching markers.
The accuracy of a test will be determined by a number of factors but primarily by the number of markers or loci that are tested. Half of a child’s markers match will match with the man that is their father and half with the woman that is their mother and so the more markers that are tested the more reliable the test becomes. Generally speaking, it is easier to use DNA to prove that two people are not closely related than to prove they are but advances in the technology mean that even home testing kits are highly effective now.
A DNA test can be used to prove paternity or maternity. As well as being able to send swabs and samples away for testing and having prenatal tests completed you can also buy what mount to over the counter DNA testing kits that enable anybody to be able to complete an accurate and effective family test from their own home although these tests will not be admissible in court or in family related cases.