At times we are faced with situations that require us to perform DNA (deoxyribonucleic acid) testing. These tests help to provide information about one’s genes and chromosomes.
There are several reasons for performing DNA tests.
In newborn screening, it helps in identifying genetic disorders early in life. It can also be used to identify a person for legal purposes for example in forensic testing which involves the use of DNA sequences to ascertain an individual’s identity. This type of testing can also be used to establish biological relationships between people, for instance in paternity tests.
A DNA test is a simple and a painless process that only requires a sample of your body cells.
The following is a step by step process of carrying out this procedure.
Collecting Buccal Swab Sample
There are several ways of obtaining a sample of your body cells. Your body cells contain a long string-like structure that constitutes your DNA which carries your genetic code. These cells are derived from your saliva, blood, skin cells or even the inside of your cheek. The fastest and most common way of getting samples is through a buccal swab/smear. This process uses a small brush or cotton swab to collect a sample of your body cells from the inside surface of your cheek.
DNA Test Laboratory
After sample collection, the swabs go to the lab for analysis. For accurate and credible results, DNA testing must be carried out in an accredited laboratory with dedicated facilities and equipment. In the laboratory, most DNA samples collected undergoes a number of processes which include:
Extraction – this refers to the process of separation of the DNA strand from the nucleus of the body cell. This routine procedure involves several stages such as separating each cell from a sample, breaking it open to release the DNA, separating the DNA from proteins and other cellular debris.
Quantitation – this is the process of determining the average concentration of DNA present in a given sample. The process also helps to isolate non-human DNA such as those found in bacteria, fungus or plant that is usually present in the total DNA recovered from the sample.
Amplification – it is a process that involves the artificial increase in the number of copies of the DNA for the purpose of characterizing it. Polymers chain reaction (PCR) is one of the methods used to amplify a single copy or a few copies of DNA. PCR takes place after adding DNA sample is added to a special chemical mix.
Separation And Sequencing – After the amplification process, DNA undergoes the separation stage. Here, the molecules containing the DNA are split at specific locations with the aim of separating them into identified chunks. The code of the particular points is analyzed to create DNA fingerprint. The fingerprints from two different DNA samples are then checked for any similarities between them.
Analysis And Interpretation – in this process, all of the pieces of your DNA are put together with the aid of a computer. A comparison is made to check if there is any variance or match between the samples and a known DNA profile. Based on the analysis, a team of experts interprets the outcome of the DNA test and arrive at an accurate conclusion.
Receiving Your Results – once the DNA test is over, the lab gives back a return result to your doctor or genetic counsellor. He will then tell you the results of your tests and answer any further questions arising. It is important to note that the time it takes to get your test results may vary depending on the DNA test taken.
Parental, genetic and forensic testing usually check to find any similarities between two biological DNA samples. This variance occurs in the section of the DNA code sequence commonly known as genetic markers. Since all our body cells contain an exactly similar DNA, it explains why it is possible to take samples from any part of our body.
The genetic markers vary from one individual to another, and this is why we are individually unique and have different traits. However, the only people that are known to have similar genetic markers are identical twins. It is also important to note that, when you are closely related to someone, the higher the likelihood that you will both share similar genetic markers.