Lower jaw shape reflects dietary differences between human populations

Mar 07, 2012

New research from the University suggests that many of the common orthodontic problems experienced by people in industrialised nations is due to their soft modern diet causing the jaw to grow too short and small relative to the size of their teeth.

The research, which was conducted by Dr Noreen von Cramon-Taubadel from the University’s School of Anthropology and Conservation, tested the long-debated theory that the transition from a largely hunter-gatherer to an agricultural subsistence strategy across many parts of the world has had a knock-on effect on the growth and development of the human skull and lower jaw.

Dr von Cramon-Taubadel compared the shape of the cranium (skull) and mandible (lower jaw) of 11 globally distributed populations against models of genetic, geographic, climatic and dietary differences. She found that lower jaw shape, and to some extent the shape of the upper palate, was related to the dietary behaviour of populations, while the cranium was strongly related to the genetic relationships of the populations.

In particular, the lower jaw reflects whether populations are primarily hunter-gatherer or agriculturalist in nature, irrespective of what part of the world they come from. This therefore suggests that chewing behaviour causes the lower jaw to grow and develop differently in different subsistence groups, while the skull is not affected in the same way.

Overall, the hunter-gather groups had longer and narrower mandible, indicating more room for the to erupt correctly, while the agriculturalists had generally shorter and broader mandibles, increasing the likelihood of dental crowding.

Dr von Cramon-Taubadel, a lecturer in Biological Anthropology with research interests in human and primate evolution, and in particular the causes of modern human skeletal diversity, said: ‘Chewing behaviour appears to cause the lower jaw to develop differently in hunter-gatherer versus farming populations, and this holds true at a global level. What is interesting, is that the rest of the skull is not affected in the same way and seems to more closely match our genetic history.’

‘Global human mandibular variation reflects differences in agricultural and hunter-gatherer subsistence strategies’ is published in Proceedings of the National Academy of Sciences.

Explore further: Oregon food label measure headed for recount

add to favorites email to friend print save as pdf

Related Stories

What shapes a bone?

Aug 05, 2011

Researchers at Johns Hopkins found that use over time and not just genetics informs the structure of jaw bones in human populations. The researchers say these findings may be used to predict the diet of an ancient population, ...

New evidence for the earliest modern humans in Europe

Nov 02, 2011

The timing, process and archeology of the peopling of Europe by early modern humans have been actively debated for more than a century. Reassessment of the anatomy and dating of a fragmentary upper jaw with ...

The skull of extinct birds revealed

Mar 21, 2011

Birds are the most diverse clade on the planet, and the skull of the living bird is one of the most highly modified and morphologically variable regions of their skeleton. The large diversity of enantiornithine ...

Changes to Embryo Can Elicit Change in Adult

Nov 08, 2005

In a study illustrating the apparent linkages between the evolutionary development and embryonic development of species, researchers have uncovered the genetic elements that determine the structure and function of a simple ...

Recommended for you

Parasitic worm genomes: largest-ever dataset released

6 hours ago

The largest collection of helminth genomic data ever assembled has been published in the new, open-access WormBase-ParaSite. Developed jointly by EMBL-EBI and the Wellcome Trust Sanger Institute, this new ...

Male sex organ distinguishes 30 millipede species

7 hours ago

The unique shapes of male sex organs have helped describe thirty new millipede species from the Great Western Woodlands in the Goldfields, the largest area of relatively undisturbed Mediterranean climate ...

How can we avoid kelp beds turning into barren grounds?

11 hours ago

Urchins are marine invertebrates that mould the biological richness of marine grounds. However, an excessive proliferation of urchins may also have severe ecological consequences on marine grounds as they ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.