When humans turned from hunting and gathering to farming approximately 10,100 years ago, they set our species on a road of genetic variation that led from longer, sturdier mandibular structures to shorter jaws better suited to chewing softer food. As a result, tooth overcrowding-and orthodontia-are now one of the hallmarks of civilization. According to a study done by researcher Noreen von Cramon-Taubadel, PhD, an anthropologist a the University of Kent in UK, global variations in jaw structure, in contrast to skull shape and facial features, are not attributable solely to genetic shift, but to a limited kind of natural selection. |