How does DNA testing work?

 How does DNA testing work?

You know the drill: Request a kit, swipe the inside of your cheek with the provided cotton swab, send it back, and get your results in a few weeks. What type of results (or the level of detail in those results) depends on the type of testing your kit provides:

Autosomal testing is the most basic and most popular means of genetic testing, commonly known as the family finder. Autosomal DNA tests look at 22 pairs of chromosomes not involved in determining a person's sex. It is used for cousin and distant relative matching as well as mixture percentages, or your ethnic mix (as shown in the percent pie charts from commercials), plus common genetic traits, like heritable diseases and hair type.

While autosomal testing shows who your relatives are, remember that this is a mix of both sides and doesn't necessarily identify which side of the family they came from.

mtDNA testing uses mitochondrial DNA to trace your mother's lineage(Opens in a new tab). These are the DNA strands passed down from mother to child. There's very little chance that these could be altered, so your direct maternal line can be traced back quite far.

Y-DNA testing focuses on the Y chromosome and traces your father's lineage(Opens in a new tab). These are the DNA strands passed down from father to son in the paternal line. It's important to note that only males can use a Y-DNA test directly — but women can usually connect their DNA profile with a father, brother, or other male relative to get these results.

mtDNA and Y-DNA tests can trace back anywhere from 20-100 generations(Opens in a new tab), while autosomal tests max out at five to eight previous generations.

Health screenings and trait analysis are the next iteration of DNA tests, jumping from just a few options (23andMe was the only reliable one for a while) to more popular kits offering some sort of look into genetic health risks and medical issues. These use your genetic markers to pinpoint potential illnesses or diseases you may be at risk of inheriting, as well as how your risks compare to other people of your age, race, and gender. Traits like hair and eye color, earlobe type, cilantro aversion, or male hair loss may also be a part of the test, providing insight into the physical and sensory genes that make you unique or genes that you're likely to pass to your children.

It's important to remember that while all of this data can be fun, in now way should it take the place of regular doctor visits and the kind of reliable testing that happens in a medical testing.