After receiving your sample, lab professionals extract DNA from cells
in your saliva. Your DNA is then chopped up into shorter strands and
copied many times via a process called amplification. Next, your DNA is
washed over a small microchip-like device that contains short strands
of synthetic DNA. The synthetic DNA fragments latch onto the pieces of
your DNA that are a complementary match. Then a laser-scanning step
reveals which strands of synthetic DNA are stuck to your DNA to
determine your genotype.