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I was born without wisdom teeth and my father was as well. My mother, brother, and sister all had them removed. Have my dad and I evolved or would this just be considered a genetic mutation?

-A curious adult from Oregon

June 08, 2007

One full week of my life, plus a month or two of misery. That is what wisdom teeth taught me!

All I can remember from the week after I got my wisdom teeth out was that my friend brought me all the movies she had in her house and a gallon of ice cream. My favorite was peach ice cream and Cinderella, but let's keep that our little secret.

As far as I can tell, if you don't have wisdom teeth, you are one of the lucky ones! We don't really know if growing wisdom teeth is stopped by mutation or even if not growing them has to do with DNA at all. This makes it hard to know for sure if you're a mutant, evolving, a result of your environment or some combination of the three.

So what would it take for not having wisdom teeth growing in to be a part of evolution? Evolution requires at least three things:

1) That there be two different traits
2) That the traits be due to DNA differences
3) That the trait increases in the population over time

We have the first one nailed for sure. You and your dad did not have wisdom teeth that grew in. Your mom's and your siblings' wisdom teeth did grow in.

The second one is a little iffier though. Some scientists think that not developing wisdom teeth is genetic, but others are not so sure. They think that not eating right or brushing your teeth well could be to blame.

This matters because the only traits we can pass on are the ones that are because of our DNA. For example, there are folks in Thailand who put rings around their necks to stretch them out. This stretching leads to very long necks. But their kids have unstretched necks because stretching doesn't affect the DNA they pass to their kids.

So to be a part of evolution, you and your dad need to not have wisdom teeth because of your DNA. But like I said, even this isn't enough.

For this DNA difference to be a part of evolution, not having wisdom teeth has to become more common in the population. Otherwise it is just an interesting DNA variation*.

So how might it become more common? One way is if not having wisdom teeth is an advantage somehow. In other words, you are more successful than your siblings because you didn't grow any wisdom teeth.

In population biology, more successful means that you have more kids who go on to survive and have more kids. Over time, not having wisdom teeth would become more common.

Let's take a fun example to make all of this clearer. I love the X-men movies, and they are good examples of DNA change and evolution. X-men are people who had a mutation in their DNA that gives them superpowers. One of the X-men is named Wolverine.

Now Wolverine heals very fast, and is super strong. This would be a really good mutation to have. You can imagine that if Wolverine had children that were very strong and could heal from any injury, they would be more likely to survive than normal people.

Over time, these folks would keep doing better. Until eventually more and more people would be like Wolverine. (Hopefully without the emotional baggage!)

Is not having wisdom teeth the same thing? That is hard to say, since wisdom teeth don't make us stronger or live longer.

Now in our past, you and your dad would certainly have been at a disadvantage. Back then people had to hunt and gather all day, and usually ended up eating grass and roots. Wisdom teeth helped us chew those awful, tough roots.

But since our food is soft and easy to eat, we don't need big mouths full of lots of strong teeth like our ancestors did. So, in evolution, our mouths have gotten smaller. Small mouths mean there is less room for teeth, so our wisdom teeth don't fit in our mouths anymore.

Wisdom teeth are no longer an advantage. So you and your dad won't be selected against. But another way for them to be part of evolution is if they are now a disadvantage. Then you and your dad would be at an advantage by not having them.

It is our modern world with its abundance of soft and easy food that has made our wisdom teeth of little use. And modern dentistry has made having them no big deal either.

It is hard to imagine that you will do significantly better than your brother or sister just because you were born without wisdom teeth. Now if a plague wipes out all the dentists tomorrow, it might be a different story. But that doesn't seem too likely.

Of course, there are other ways for a trait to become more common. Imagine you are stranded on a deserted island with only one other person. The two of you have kids and found a new population. Because of you, this new population will be less likely to have wisdom teeth.

Not because of some advantage. But because of luck, one of the founding members just happened to not have wisdom teeth. This is called the founder effect.

So there you have it. If your lack of wisdom teeth is genetic, then you can pass it on to your kids. And if your descendants form a larger percentage of a future population, then your lack of wisdom teeth could be a part of human evolution. Two big ifs at this point.

*If a DNA change is recent, it is called a mutation. If it is older, then it is variation. The older variation came from a mutation from long ago.

Evolution requires that
the trait be genetic.