Are wisdom teeth becoming obsolete?
For many of us, it may seem like our wisdom teeth didn't get the memo that our evolved jaws are lacking space. But some people never develop wisdom teeth; in fact, these teeth don't appear in about 35 percent of the population [source: Spinney]. Are we on an evolutionary track to losing them altogether?
Some experts say it's possible these teeth will eventually disappear [sources: Flam, Usbourne]. Still, there are a few unknowns in the equation. Scientists aren't sure of the role that DNA plays in creating teeth at the third molar position [source: Colf]. Third molars develop entirely after birth, the only teeth to do so. Because these teeth aren't present at birth, it may be harder for nature to select against them [source: LePage]. For wisdom teeth to form, the tissue that starts the process of tooth building has to migrate back in the mouth to interact with the back jaw tissue. If this migration doesn't happen, then no tooth will grow there.
There may also be some environmental factors at work, including disease or head trauma, that stop the tissue migration [source: Silvestri, Singh]. It could also come down to differences in how various cultures use their jaws. For example, in the 1970s, researchers tied the larger jaw that was present in Eskimo women to their tradition of chewing leather to soften it. In parts of East Asia, it's more common to find people with fewer wisdom teeth, if any [source: Vines]. If people of a culture have reached the point where they don't use a trait, they may lose it.
But some scientists are beginning work on stopping the teeth from appearing altogether, so that we might bioengineer these teeth out of existence before evolution does it for us. Because there's a window of time in which there's no third molar, it might be possible to administer a laser or a chemical agent that would prevent the tooth growth. Preliminary studies have shown some success in dogs and rats [source: Silvestri, Singh].
Currently, the lack of wisdom teeth doesn't produce any great evolutionary advantage, particularly with the abundance of oral surgeons who can remove the wisdom teeth that do emerge. That makes it hard to say exactly how the trait might adapt in the future. Certainly, oral surgeons probably have their fingers crossed that these teeth continue to appear for a good long while. The rest of us will have to make do with lots of ice cream and the continuous exchange of surgery stories. Sure, those wisdom tooth lackers may claim they're more highly evolved because they don't have to go through a few days of misery, but what do they talk about at boring parties?
More Great Links
- Bergman, Jerry. "Are wisdom teeth (third molars) vestiges of human evolution?" Creation ex nihilo Technical Journal. December 1998. (July 28, 2008) http://www.answersingenesis.org/tj/v12/i3/wisdomteeth.asp
- Blakeslee, Sandra. "Study Questions Routine Molar Removal." New York Times. June 26, 1991. (July 28, 2008) http://query.nytimes.com/gst/fullpage.html?res=9D0CE5DD1539F935A15755C0A967958260&scp=38&sq=%22wisdom+teeth%22&st=nyt
- Colf, Leremy. "Ask a Geneticist." Understanding Genetics. June 8, 2007. (July 28, 2008) http://www.thetech.org/genetics/ask.php?id=223
- Cooper, Rachele. "Why Do We Have Wisdom Teeth?" Scienceline. Feb. 5, 2007. (July 28, 2008) http://scienceline.org/2007/02/05/ask-cooper-wisdomteeth/
- Flam, Faye. "Mankind not done evolving yet." Philadelphia Inquirer. April 24, 2008.
- Friedman, Jay W. "The Prophylactic Extraction of Third Molars: A Public Health Hazard." Health Policy and Ethics. September 2007.
- LePage, Michael. "Evolution myths: Everything is an adaptation." New Scientist. April 16, 2008. (July 28, 2008) http://www.newscientist.com/channel/life/dn13615-evolution-myths-everything-is-an-adaptation.html
- Silvestri, Anthony R. Jr. and Iqbal Singh. "The unresolved problem of the third molar: Would people be better off without it?" Journal of the American Dental Association. 2003. (July 28, 2008) http://jada.ada.org/cgi/reprint/134/4/450
- Spinney, Laura. "Remnants of Evolution." New Scientist. May 17, 2008.
- Usborne, Simon. "Meet the Ancestors: Lucy is Going on Display Outside Africa for the First Time." Red Orbit. Aug. 1, 2007. (July 28, 2008) http://www.redorbit.com/news/science/1019044/meet_the_ancestors_lucy_is_going_on_display_outside_africa/index.html
- Vines, Gail. "A waste of space." New Scientist. April 25, 1998. (July 28, 2008) http://www.newscientist.com/article/mg15821315.200-a-waste-of-space.html
- Wielawski, Irene M. "To Pull or Not to Pull? Wisdom Teeth in Trouble." New York Times. April 26, 2005. (July 28, 2008) http://www.nytimes.com/2005/04/26/health/26teet.html?scp=1&sq=%22wisdom+teeth%22&st=nyt
- Wilford, John Noble. "Less Jaw, Big Brain: Evolution Milestone Laid to Gene Flaw." New York Times. March 25, 2004. (July 28, 2008) http://query.nytimes.com/gst/fullpage.html?res=9C04E7D81530F936A15750C0A9629C8B63&sec=&spon=&pagewanted=all