Mice teeth explain the troubles with human wisdom teeth

Sep 26, 2007

During evolution, many of a species’ properties are shaped by ecological interactions. This is readily evident in mammalian teeth, whose many features closely reflect what each species eats. However, for a long time scientists have suspected that genetic and developmental interactions may also influence species-specific properties.

Now, researchers at the University of Helsinki’s Institute of Biotechnology show how development affects the evolution of teeth, and have devised a simple developmental model to predict aspects of teeth across many species. The results were published in Nature.

In the study in the field of evolutionary developmental biology, the researchers Kathryn Kavanagh, Jukka Jernvall and Alistair Evans in the Institute of Biotechnology of the University of Helsinki first studied cheek tooth, or molar, development in mice. Similarly to human teeth, mouse molars develop from front-to-back so that the first molar appears first and the posterior molars bud sequentially along the jaw. Normally the last molar to develop is the third, or wisdom tooth.

Experiments on cultured mouse molars revealed that the size and number of posterior molars depend on previously initiated molars. The mechanism, called an ‘inhibitory cascade’, acts much like a ratchet that cumulatively increases size differences of teeth along the jaw.

By quantifying their experiments, the researchers constructed a simple mathematical model which they then used to predict relative size and number of molars across many other mouse and rat species. They show that the model accurately predicts tooth proportions and numbers, one curious effect being that the second molar makes up one-third of total molar area, irrespective of species-specific molar proportions.

This new research demonstrates that with advances in the study of the molecular regulation of development, it is now possible to identify how development influences evolution. And this may help explain the troublesome wisdom teeth of modern humans - the blame may lie within a weak inhibitory cascade that allows the development of the last molar in a jaw that is too small.

Source: University of Helsinki

Explore further: Researchers collect soil samples from around the globe in effort to conduct fungi survey

add to favorites email to friend print save as pdf

Related Stories

Woolly mammoth skeleton sold at UK auction

Nov 26, 2014

The skeleton of an Ice Age woolly mammoth fetched £189,000 ($300,000, 239.000 euros) at auction Wednesday as it went under the hammer in Britain with a host of other rare or extinct species.

New progress of the Neogene Suidae research

Oct 17, 2014

Dr. Hou Sukuan and Prof. Deng Tao from the Institute of Vertebrate Paleontology and Paleoanthropology(IVPP), Chinese Academy of Sciences reported a new species of Chleuastochoerus from the Linxia Basin, Gansu ...

Recommended for you

Parasitic worm genomes: largest-ever dataset released

19 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

19 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?

23 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.