What happens to my sample in the lab?

Are you curious about what happens with your saliva sample? We have prepared a short summary of all the activities and processes that must be carried out before we upload the results of your DNA analysis to your profile. Want to know how it works? Read on.

How is it possible to read anything from saliva?

Collection in the form of a saliva swab has several advantages compared to blood sampling, such as longer sample stability, painlessness, and the possibility of performing the collection without the need for medical personnel. After collecting a saliva sample, the object of examination is not the fluid itself, but the cells of the oral mucosa epithelium that are found in it. These cells contain DNA in their nucleus, which is composed of nucleotides (A, G, C, T). Nucleotides are molecules that, like 1 and 0 in computer science, serve to store information for a cell about how it should look and behave. DNA is also a source of information for us, since today we can read it effectively with powerful technologies.

In our case, this information is individual genetic variants, so-called SNP polymorphisms. Single Nucleotide Polymorphism (colloquially “snip”) represents a change in a single nucleotide in the sequence of our genome at a specific location. This change is heritable and occurs in the population with a certain frequency (usually more than 1%). In most cases, these are common differences between individuals that have been associated with the likelihood of a certain trait in scientific studies in the past.

How is the process of processing, analyzing and evaluating my sample carried out?

The sample is sent to the laboratory marked only with a unique code to ensure its anonymity. Once the saliva sample reaches the laboratory, it is taken over by professional personnel who perform a series of validated laboratory procedures necessary to obtain the required high-quality data.

The first step is the isolation of the DNA itself. This is done either through a column, i.e. a kind of miniature filter that captures only the DNA and lets other impurities pass through, or using magnetic beads that capture the DNA directly from the solution with the sample.

After isolation, the sample is prepared for scanning, which takes a total of 3 days. It consists of amplifying the DNA during overnight incubation to obtain sufficient information to detect the signal. The amplified DNA is then cleaved into shorter pieces using enzymes. Cleaving the DNA into short fragments is necessary because only short fragments are able to effectively attach to a large number of specific sequences on the chip (so-called probes), which is the next step in the analysis. Individual probes are designed to capture information about the polymorphisms that we are interested in.

After the specific pairing of DNA fragments from the sample with the sequences on the chip, the detection phase follows. In this phase, a solution containing 4 different labeled nucleotides A, G, C, T is added to the surface of the chip. The respective enzyme then assigns 1 specific nucleotide to the area of ​​our interest, which in our case is the selected SNP polymorphism. After the assignment of the complementary base, the chip scanning phase follows. In this phase, the sensor captures individual fluorescent signals and converts them into digital form, which is then evaluated by the appropriate software. This reaction occurs simultaneously at hundreds of thousands of locations on the chip, which allows the analysis of up to approximately 700,000 SNPs for each sample and can process multiple samples simultaneously.

The output of this analysis is raw data containing information about individual scanned locations on the chip. In the next steps, the analysis is focused on the quality of detection and evaluation of the entire genotyping process. The final result of the analysis is therefore a set of all analyzed SNP polymorphisms with an evaluation of their status in a given person.

The entire process takes place in modern laboratories with the highest possible level of automation and robotization to ensure high efficiency and minimize errors caused by the human factor. And how do we know that the analysis was carried out correctly? For each sample, the accuracy of the analysis is evaluated based on the so-called call rate value. If this value is not high enough, the analysis must be repeated. This process is provided by our customer support.

What will the laboratory do with my sample after analysis? 

After the analysis is completed, the samples and data are stored in the laboratory for 3 months. The data obtained from the analysis is sent by the laboratory to us for further processing and you can view the individual results after logging into your secure account in our web application. You also have access to the raw data from the analysis in your account. Would you like to see what the sample results of our DNA analysis look like? View them in the DEMO version of the application.