What’s In Your DNA?

How Do We Get It?

When your cheek swab arrives at the state-of-the-art testing facility, it is put through a series of solutions to extract your DNA. Through a process known as polymerase chain reaction (PCR), we increase the amount of the specific DNA segments on the gene that we want to test. The process involves heating the solution with the DNA to the temperature at which the two sides of the DNA molecule separate. We then add specific primers which have been designed to stick to the single strands of DNA at the beginning MTL Genetic analyzer and at the end of the specific segment we want to analyze.

The temperature is then lowered so the two chains can recombine. We then add a DNA polymerase to the solution which attaches to the strands of DNA at the sites where the primer has attached. Then a solution containing an abundance of the four base pairs, G, C, A and T, is added to the vessel and the DNA polymerase starts building a complementary DNA chain to the targeted area on the DNA. Time is allowed for the reaction to complete.

The temperature is then raised again to separate these segments and the process is repeated. One cycle lasts about four minutes and is repeated 20 to 30 times, yielding billions of copies of the targeted DNA sequence, all from the few cells that were contained on the cheek swab. Now that there is a significant amount of DNA with the target sequence, it can be put into an analyzer to determine what substitutions might be present in the sequence.

What Can It Tell You?