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.
The article Predicting evolutionary patterns of mammalian teeth from development by K. Kavanagh, J. Jernvall and A. Evans will be published in Nature September 27th.
Maria Peltonen | alfa
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22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden
The pyrenoid is a carbon-fixing liquid droplet
22.09.2017 | Max-Planck-Institut für Biochemie
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
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Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
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