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Officially called third molars, wisdom teeth get their common name because they only appear when you're more mature. Typically they show up in your late teens or early 20s. An AncestryDNA® test can tell you what some of your DNA suggests about whether all of your wisdom teeth will come in or not.

Purpose of Wisdom Teeth

Wisdom teeth had a purpose for our ancestors. They ate a lot of tough roots and vegetables that were hard to chew. A set of extra molars came in handy for really grinding up that food.

Wisdom TeethNowadays we cook our food to soften it up. So wisdom teeth are now vestigial, or something that once served a purpose but no longer does. In fact, today wisdom teeth are more often a problem for people, sometimes causing issues, such as swelling, infection, and bleeding in the mouth.

Genetics of Wisdom Teeth

Are wisdom teeth genetic? The answer is complicated.

AncestryDNA looks at a marker in the THSD7B gene on chromosome 2, along with other genetic markers related to wisdom teeth, to estimate whether or not you developed all four wisdom teeth.

But there are still a lot of unknowns about the role genetics plays in tooth development — and particularly wisdom teeth because they aren't present at birth like the rest of your teeth are.

As the genetics are complicated, and there may be other factors at work besides just your genes, this trait is hard to predict. So even if your genetic markers predict an absence of wisdom teeth, you may still have them.

Does Everyone Have Wisdom Teeth?

If you look at wisdom teeth evolution, you'll see that at some point our ancestors started losing their wisdom teeth. One reason why this happened may be because they started eating softer, cooked food and, as mentioned, no longer needed wisdom teeth. Eventually, one of our ancestors had a change in one or more of their genes and never grew that third set of molars.

Over time, as our jaws got smaller and couldn't fit wisdom teeth easily, that variation spread. Now roughly a fifth of the world's population has no wisdom teeth or is missing one or more of their wisdom teeth. Some experts think humans will eventually lose them altogether.

Interesting Facts About Wisdom Teeth

Scientists have learned at least two reasons why you may not see wisdom teeth in your mouth. One study found if you received numbing shots in your gums between the ages of two and six, then you were over four times less likely to have wisdom teeth later in life. The anesthesia appears to disrupt the development of the third molars.

Anesthesia isn't the only reason why you may not have wisdom teeth. Your ethnicity may also play a role. A study found that 10% to 25% of Americans with European heritage were missing at least one third molar. Among the Inuit, 45% are missing wisdom teeth.

References

Ancient Mutation Explains Missing Wisdom Teeth. Live Science. March 13, 2013. https://www.livescience.com/27529-missing-wisdom-teeth.html.

Are wisdom teeth vestigial structures? UCSB ScienceLine. July 9, 2002. http://scienceline.ucsb.edu/getkey.php?key=147

Carter K, Worthington S. Morphologic and Demographic Predictors of Third Molar Agenesis: A Systematic Review and Meta-analysis. Journal of Dental Research. 2015;94(7):886–94. https://www.ncbi.nlm.nih.gov/pubmed/25883107.

Haga S, Nakaoka H, Yamaguchi T, et al. A genome-wide association study of third molar agenesis in Japanese and Korean populations. Journal of Human Genetics. 2013;58(12):799–803. https://www.ncbi.nlm.nih.gov/pubmed/24172245.

Missing Wisdom Teeth in Children: Are Anesthesia Injections to Blame? Medical Daily. April 3, 2013. https://www.medicaldaily.com/missing-wisdom-teeth-children-are-anesthesia-injections-blame-244886.