Inside Our Lab
The test procedure begins once your saliva sample arrives at our laboratory. The first step is DNA isolation and detection. Your samples will be transferred to the skilled hands of our DNA technicians, who follow a carefully optimized protocol of DNA isolation, DNA amplification, and DNA detection.
During the detection reaction, we extract the information hidden in your genes. The final step is DNA sequence data interpretation, wherein our highly qualified DNA experts capitalize on their decades of DNA research from leading institutions around the world.
Using the latest advances in the field of bioinformatics, our DNA experts will prepare a detailed report indicating the presence of any SNPs and any potential risk for disease.
PCR and DNA Fragmentation
The amount of DNA in the original sample is very low, so the sample must be amplified to provide enough material for APEX detection. This amplification occurs during a chemical reaction called PCR (polymerase chain reaction), wherein each DNA molecule is copied many times, creating billions of copies of each molecule by the end of the reaction.
Only selected regions of DNA that may potentially contain SNPs linked to certain diseases are amplified in order to minimize the time and reagents used in this reaction. DNA molecules are very long, and for ease of handling, they are fragmented into smaller pieces after the amplification.
The next step is critical for a successful detection of SNP. During this step, the fragmented DNA mixture from the previous step is transferred to the chip, on which short single-stranded DNA molecules called primers are chemically attached. A reaction mixture contains nucleotides for DNA synthesis as well as the four DNA terminator nucleotides labelled with fluorescent dyes - each nucleotide with a distinct color.
When a terminator nucleotide is incorporated into the DNA molecule, the synthesis of this particular molecule stops. By the end of this reaction, an array of DNA fragments of different sizes each labelled with a unique color depending on the terminator nucleotide is generated. This reaction is carefully optimized to obtain the highest signal-to-noise ratio and to ensure the specificity of detection.
For SNP detection, the chips with fluorescently labeled DNA arrays are visualized in a QuattroImager, a device equipped with four lasers and a highly sensitive, specialized camera. The fluorescent color patterns are recorded and then analyzed by the Genorama Genotyping Software, which converts the image information into DNA sequence data. This sequence data is then used for SNP detection.
Data Analysis and Interpretation
Using the DNA sequence data, the DNA expert, in collaboration with bioinformaticians, determines the presence of SNPs in the DNA regions related to disease. Comparing this information with previous knowledge, the DNA expert then computes the risk of acquiring a particular disease. A detailed analysis containing sequencing information and the presence of any SNPs is delivered to the client.