What is Genetic Testing?
A genetic test (or DNA test) for family history purposes is designed to look for variations in peoples’ DNA that can tell us something about them. For example, genetic testing can determine where a person’s ancestors came from five to 20 generations ago. DNA testing can also provide information about genetic traits, such as whether someone is more or less likely to be a sprinter, sun sneezer, or able to tolerate dairy products .
How Is Genetic Testing Done?
A DNA test can be done with a simple saliva sample, which contains cheek and immune system cells. That’s all that’s required for an analysis since every cell in your body contains your DNA and your unique genetic code. There are several different types of genetic tests—all of which begin by extracting your DNA from the cells in your sample and preparing it for analysis.
Does a Genetic Test Look at All of Your DNA?
Genetic tests don’t typically look at all of your DNA. What they do look at depends on the type of genetic test you choose .
There are many different ways to gather information from a DNA sample and, while reading the entire length of a person’s genome is possible, it’s not always necessary. Doing so is currently very expensive and can create more information than scientists know what to do with. Human DNA is about 99.9% identical from one person to the next, so genetic tests often focus on specific areas of a person’s genetic code, called markers, which are known to contain useful information.
What Are the Different Types of Genetic Tests?
There are three main types of DNA that can be used for consumer genealogical DNA testing.
Mitochondrial DNA (mtDNA): This is a test that looks only at the DNA inherited from the biological mother, meaning it only reveals information about the maternal side of the family.
Y-DNA: This test looks at the Y chromosome, which typically only appears in biological males. As a result, women (who are usually born with two X chromosomes) would not take this test. These DNA test results only show information about the paternal side of the family.
Autosomal DNA: This test looks at DNA across a person’s whole genome. This means anyone can take it to uncover information about both sides of the family tree, maternal and paternal.
What Type of Genetic Test Is Best?
The type of genetic test you choose depends on the kind of answers you want. For people who want to learn about their family’s roots, the autosomal DNA test is typically the best option for genealogical DNA testing. It’s usable by anyone and can reveal details about both sides of your family tree. The autosomal DNA test can also be used to indicate genetic traits related to personality, physical appearance, and fitness, for example.
AncestryDNA® uses autosomal DNA testing, as it’s the best type overall for people interested in family history. AncestryDNA test results can generate your ethnicity estimate—information about where your ancestors came from—and it can connect you with new relatives on both sides of your family .
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