Historically, experts have always collected DNA from the blood. It is practical, efficient and time-tested. However, it’s chaos when you extract DNA from blood. Collecting blood samples from people can be tricky – not only is it time-consuming to get to a hospital or doctor (not to mention the needles!), but the costs of transport, storage, and handling are high.
2011 the medical board approved the saliva nucleic acid solution/purification/extraction kit. It is faster and less intrusive. Saliva is now the go-to DNA collection method. It is less invasive and more affordable. Spit DNA collection through human saliva can help in significant medical conditions.
What to Keep in Mind While Collecting Saliva?
It is essential to follow the collection instructions strictly. Ensure subjects are salivating and not eating/drinking/smoking/chewing gum for 30 minutes before sample administration. If these recommendations are not followed, DNA yield may be reduced.
Bubbles in saliva are not counted. Ensure the liquid saliva is in the “Fill To” line; all the bubbles should be above the line. It ensures an optimal amount of saliva. The quality will not be affected if you collect less saliva, but the DNA yield will decrease accordingly.
DNA yields vary from donor to donor. Testing samples from different donors is vital to understand the expected performance accurately. Many donors have difficulty producing 2 ml of saliva. They can solve this by rubbing the cheeks just behind the back teeth.
You can also stimulate saliva production using a pinch of sugar on your tongue. You only need a small amount, just enough for a person to taste it. A drop of lemon juice also collects the saliva in the saliva nucleic acid solution/purification/extraction kit. Using a non-salvageable collection kit makes sampling easier for you and the donor and ensures proper DNA collection.
Medical Professionals Derive the DNA in Saliva from Buccal Epithelial and White Blood Cells
You may be surprised to learn that there is a lot of confusion surrounding the source of salivary genomic DNA. Surprisingly, most people assume salivary DNA’s source is strictly oral epithelial cells. However, studies show up to 74% of salivary DNA originates from white blood cells, an excellent source of high-quality genomic DNA. Since saliva produces virtually the same amount of DNA as blood and has the same quality and volume of DNA, it can be considered equivalent to blood in genetic applications.
The Vast Majority of the Human DNA in Saliva Contains Bacteria.
Although most researchers prefer large amounts of DNA, technological advances in upstream platforms now allow even small amounts of DNA to be tested, provided the DNA is of sufficient quality. As stated above, most of the DNA in saliva comes from white blood cells.
The buccal swabs contain around 2 mL of saliva. The saliva may contain bacteria that the researchers can use to study the individual’s health. It tells a lot about their underlying health issues. It allows health professionals to examine the person’s medical history. By analysing that sample, the doctors can offer expert advice and cure accordingly.
