What is Autosomal DNA?

Autosomal DNA comes from the 22 autosomal chromosome pairs we each inherit from our parents. (We inherit 23 chromosomes total: the 23rd is the sex chromosome.) 

Why is Autosomal DNA Important?

As humans, nearly all of our autosomal chromosomes are the same. It’s what makes us genetically human.

However, our parents pass on some tiny variations. So, even though we may be 99.9% identical to each other, that 0.1% difference is essentially how we can tell each other apart. That variety accounts for many of the differences in our physical bodies and traits.

Autosomal DNA Testing

How Does Autosomal DNA Testing Work?

Autosomal DNA tests look closely at that small fraction of our chromosomes where we find the variety between us. They compare our DNA with that of other people who have tested at the same company. Those who share a lot of common DNA show up as DNA matches and may be relatives.

Autosomal DNA tests also include what are commonly called “ethnicity estimates.” These compare your DNA with the DNA of people who have ancestors in specific parts of the world. The result is an estimate of what percentage of your genetic heritage comes from different ancestral places or populations.

Which DNA Testing Company Should I Use?

When it comes to the question, “Which testing company should I use?” it’s best to ask what you’re looking to get out of a DNA test. If you’re interested in using your DNA to find relatives, the biggest pools of testers are at AncestryDNA and 23andMe, but 23andMe doesn’t have as many tools to help you figure out how you’re related. MyHeritage and Family Tree DNA are available globally, so you may be more likely to find relatives in certain parts of the world using these companies. MyHeritage has stronger tools for figuring out your family connections. If you’re most interested in your DNA ethnicity estimates (where your ancestors were from), you’ll want to choose a testing company that breaks down your ancestral places into the most detail. For a much more detailed comparison, including comparisons of different ancestral places/ethnicity reports, read “Which DNA Test is Best for Ancestry.”

How Much Does DNA Testing Cost?

Autosomal DNA testing ranges in price between $79 and $99 USD (before shipping). However, the companies sometimes run sales, so you may not need to pay this much, especially if you’re not in a hurry and could wait until the next sale (often during March for St. Patrick’s Day, April for DNA Day, May for Mother’s Day, June for Father’s Day, and so forth).

See a detailed breakdown of prices and which tests are available in your country in our article: “Which DNA Test is Best for Ancestry.”

How Does Autosomal DNA Testing Differ from Other Genetic Genealogy Tests?

The two other kinds of DNA tests sold for genealogical purposes are YDNA and mtDNA. An autosomal DNA test differs from mtDNA and Y-DNA tests in several important respects. First, as stated above, an autosomal DNA test uses the 22 autosomal pairs located inside the nucleus of your cells rather than the sex chromosomes. Second, autosomal DNA tests can detect your genetic relatives on any branch of your family tree, while mtDNA only connects with relatives on your maternal lineage, and YDNA only connects with relatives on a genetic male’s male lineage. Finally, autosomal DNA testing is only sensitive to genetic connections within the past 3-6 generations, while YDNA and mtDNA connections go many, many generations deeper.

Autosomal DNA is by far the most popular kind of DNA test. It is better at connecting people with recent relatives on all branches of their family. Millions of people around the world have taken autosomal DNA tests.

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