“When did you last have your dental clean up/exam”, asked the front desk nurse. I thought for a long time, trying to visualize the mental image of the dentist so that I may be able to place the time point of my earlier visit. No idea. But I know, this was long before I started graduate school. “7 years”, “or so”, I said. Then I stood there, witnessing a quick stare, darted by an expression of disapproval on my nurse’s face.
I made a trip to a dentist a few days back. After a rigorous hour and half appointment consisting of X-Rays, drilling and intense poking, I was seated next to the dentist who was pouring over my results. Turns out, that my calcified arrangement of my ectodermal tissues a.k.a teeth, were in near-perfect condition. While I was cheering inside, mentally putting off my next doctor’s visit for another 7 years, my dentist eyes sparkled. He said, very flatteringly – “you have genetically superior teeth”! I giggled, not knowing why. His remark was based on my absolute inability to possess the supernumerary structures, pompously called wisdom teeth.
No kidding, wisdom teeth are extremely painful, annoying, irritating, unnecessary, and expensive, and sometimes even dangerous to get rid of. Someone out there, had that sense of humor to name it ‘wisdom’ teeth, although it was historically named to signify the time at one’s life during which these molars usually begin to appear – between 15 & 25, an age bracket where many would have (supposedly) pursued wisdom by way of education or through life experiences. That name, however, was clearly oblivious to the irony it had created among uninformed school students who thought they weren’t wise enough to have extra molars erupting from beneath their gums. While most of the us – members of the constantly evolving human race- have been genetically selected against the need for these extra molars in our jaw line, a few of us still develop them. Clinically, they are vestigial structures, which were critical for human ancestors to be able to chew harder food and foliage. Importantly, teeth was crucial for survival of the prehistoric man who valued his sharp teeth for attacking, clutching and consuming his prey. As we evolved, we began standing up and used limbs for that purpose. Moreover, having numerous teeth was probably advantageous at a time when survival meant the fittest (the medical insurance then, was also pretty bad, just like it is in the States now).
A quick google search indicates that over 35% of the world population don’t have wisdom teeth, while it is intriguing to me why some of us still do. A few chromatin modifier genes have been implied in expressing the PAX6 gene responsible for wisdom teeth eruption. However, not much genetic data seems to exist on PubMED (a medical database of research findings). Moreover, without any evolutionary advantage for not having those extra molars, it is likely not to become extinct.
Now with full genomes of most organisms being sequenced, living or fossilized, we now have access to understanding the millions of genes (which gave rise to anatomical structures) that our ancestors possessed and those we don’t anymore. But not all vestigial structures that became extinct are useless to us now. There are tons of examples for that, but I’ll share the one I just found out. While reading this article, I found out that human ancestors had once harbored the gene L-gulano-γ-lactone oxidase that allowed them to synthesize their OWN vitamin C! Modern man, unfortunately doesn’t have it.
So, crank up on those berries and lemons.