Today, just about everyone is at least somewhat familiar with the practice of DNA testing and analysis. But at best they only have a vague understanding of the process.
And that’s not ideal considering that genetic testing is common these days.
It’s used for genealogical research on platforms like Ancestry.com and MyHeritage.com, it’s a key law enforcement technique, and it’s even used as a diagnostic tool for detecting certain inherited medical conditions.
For that reason, it’s a good idea to have a working understanding of how a laboratory can take a hair, skin, or saliva sample and use it to create a genetic profile.
And although the scientific aspect of the process isn’t simple, the nuts-and-bolts procedure used is straightforward. To elaborate, here are the four major steps involved in a laboratory DNA analysis.
By the end, you’ll know just what happens after your doctor swabs your cheeks and sends it off for testing – and why it’s such an important scientific and medical innovation in the first place.
1. DNA Extraction
When a biological sample first arrives at a lab, it’s not in a state that’s useful for genetic testing.
To get it there, technicians must first separate the DNA molecules from any other material that may be present in the sample.
This is important not only because it makes the subsequent steps easier to perform, but also because there are plenty of substances that could interfere with the further processing of DNA.
For example, the hemoglobin that forms significant portions of red blood cells, and even the indigo dye found in certain types of clothing can contaminate a DNA sample enough to render it useless.
Once all of a sample’s DNA molecules are separated out, the next step in the process is counting how many molecules are present – and making sure that they’re all human.
This is a critical phase of the testing process.
That’s because an insufficient quantity or quality of DNA molecules can make further testing impossible. There are a variety of methods used to complete this step.
In any case, once the DNA sample is tested to assure sufficient quantity and quality, it’s ready for the next step in the process.
Because DNA samples get destroyed in the testing process, one of the key innovations that made wide-scale DNA testing possible is the ability to make as many exact copies of a subject molecule as needed.
This is called amplification. That’s why the previous step is so important – without it, the laboratory would end up making flawed copies that rendered the analysis unusable.
To make the copies, a process called a polymerase chain reaction (PCR) is used. This involves heating and cooling the sample repeatedly along with a substance called DNA polymerase.
This causes the polymerase to start replicating the complete DNA contained in the sample, producing as many copies as needed for further testing.
4. Capillary Electrophoresis
The last step in the process is to separate all of the new DNA sample copies created in the amplification stage from the DNA polymerase mixture.
This makes it possible to analyze the individual DNA molecules to develop a genetic profile.
Fortunately, DNA molecules carry a negative ion charge, making it simple to pull them out of the mixture.
To do it, a technician uses a set of tiny tubes – capillaries – and an electric field to push the negatively-charged DNA molecule into them.
From there, they can be fed into a machine called a genetic analyzer which creates a data representation of the DNA’s specific sequence.
Your DNA as Data
After making it through the four-step testing process detailed above, it’s possible to store the sample’s DNA pattern as data for further study.
Most people have seen the results of such tests represented by a strip of horizontal marks, each varying in size and intensity.
But what’s most important is what doctors and scientists can do with the data.
Using DNA analysis, it’s possible to find familial connections and other genealogical data. But its most common use today is to conduct screenings for myriad genetic disorders.
In some cases, detecting genetic abnormalities allows for early treatment and can eliminate the effects of certain diseases completely.
Or, it could exclude you from the need for further monitoring for a variety of conditions, simplifying future medical care.
In both cases, DNA testing has improved medical outcomes for countless millions around the world.
So, the bottom line here is – your DNA holds clues as to your future health prospects that can help you live a better, healthier life.
And the process of sorting out life’s most basic building block, while complicated, isn’t as complex as you may have once thought.
And either way, it’s still an amazing and underappreciated scientific breakthrough that’s still helping medical science improve today.
And now, you know a bit more about the process that makes it all possible – making it all the more impressive to be sure.