The World's First Farmers Had Bad Teeth: The Evolution of the Jaw

It turns out that dental crowding may have evolved among the world's very first farmers. Scientists have examined the teeth of hunter-gatherers and early farmers, and have found that dental crowding first became common among formers about 12,000 years ago in Southwest Asia.

In order to better understand the difference between hunter-gatherers and farmers, the researchers analyzed the lower jaws and teeth crown dimensions of 292 archaeological skeletons from the Levant, Anatolia and Europe that were dated between 28,000 and 6,000 years ago. Just from examining the forms and structure of the jawbones, the researchers found a clear separations between European hunter-gathers, Near Eastern/Anatolian semi-sedentary hunter-gatherers and transitional farmers.

"Our analysis shows that the lower jaws of the world's earliest farmers in the Levant, are not simply smaller versions of those of the predecessor hunter-gatherers, but that the lower jaw underwent a complex series of shape changes commensurate with the transition to agriculture," said Ron Pinhasi, one of the researchers, in a news release. "Our findings show that the hunter gatherer populations have an almost 'perfect harmony' between their lower jaws and teeth. But this harmony begins to fade when you examine the lower jaws and teeth of the earliest farmers."

The diet of hunter-gatherers was based on "hard" foods like wild uncooked vegetables and meat. In contrast, the diet of farmers was based on "soft" cooked or processed foods like cereals and legumes. With soft, cooked foods, there is less of a requirement for chewing. This, in turn, lessens the size of the jaws-but doesn't result in a corresponding reduction in the dimensions of the teeth. This causes dental overcrowding.

The findings reveal a bit more about the link between teeth, chewing and diet. Not only that, but it shows how dental crowding evolved in modern-world populations.

The findings are published in the journal PLOS One.

For more great science stories and general news, please visit our sister site, Headlines and Global News (HNGN).