Parents going broke to pay for their offspring’s braces and orthodontistry can finally blame somebody besides their mildly malformed children: our farmer ancestors. A study published this week in the Proceedings of the National Academy of Sciences found that people living in subsistence farming communities around the world have shorter, wider jaws than those in hunting and gathering societies. This leaves less room for teeth, which have changed little in size or abundance over human history—and may help explain why crooked choppers and a need for orthodontia are so common, study author Noreen von Cramon-Taubadel tells the BBC.So is it a genetic trait, or is it the environmental factor (as in consumption of grains)? I would say the latter.
Previous studies have shown that differences in the length of jawbones seem to arise relatively quickly after a change in subsistence economy, suggesting the shift to a shorter jawbone in agricultural groups could reflect a selective pressure for downsizing.Or it suggests that it is environmental (as in consumption of grains).
Changes in jawbone size can also arise within a single generation due to phenotypic plasticity, wherein environmental differences lead to anatomical changes. For example, a 2004 study found that the mandibles of hyraxes (a small rodent-like mammal) given soft, processed food grew to be 10 percent shorter than those fed a heartier unprocessed diet.
Or it could be that is the consumption of grains.
Perhaps one day this “mismatch” will correct itself. Until then, were stuck with braces.Or we could try changing our diet and see if we are really "stuck" with this.