highlights

publications

Mechanical positional information guides the self-organized development of a polygonal network of creases in the skin of mammalian noses.

The glabrous skin of the rhinarium (naked nose) of many mammalian species exhibits a polygonal pattern of grooves that retain physiological fluid, thereby keeping their nose wet and, among other effects, facilitating the collection of chemosensory molecules. Here, we perform volumetric imaging of whole-mount rhinaria from sequences of embryonic and juvenile cows, dogs, and ferrets. We demonstrate that rhinarial polygonal domains are not placode-derived skin appendages but arise through a self-organized mechanical process consisting of the constrained growth and buckling of the epidermal basal layer, followed by the formation of sharp epidermal creases exactly facing an underlying network of stiff blood vessels. Our numerical simulations show that the mechanical stress generated by excessive epidermal growth concentrates at the positions of vessels that form rigid base points, causing the epidermal layers to move outward and shape domes-akin to arches rising against stiff pillars. Remarkably, this gives rise to a larger length scale (the distance between the vessels) in the surface folding pattern than would otherwise occur in the absence of vessels. These results hint at a concept of "mechanical positional information" by which material properties of anatomical elements can impose local constraints on an otherwise globally self-organized mechanical pattern. In addition, our analyses of the rhinarial patterns in cow clones highlight a substantial level of stochasticity in the pre-pattern of vessels, while our numerical simulations also recapitulate the disruption of the folding pattern in cows affected by a hereditary disorder that causes hyperextensibility of the skin.

news

How the dog, cow and ferret make their noses

Milinkovitch's team found that nose patterns form in embryos due to differential skin growth supported by blood vessels.

events

Understanding Architecture And Evolutionary Patterns In Haplolepidous Peristomes (Dicranidae, Bryophyta) Using Histology And Micro-Morphology

25.07.2023 14:00, Salle de conférence (Museum of Natural History)

Mathilde Ruche (Michelle Price's group).
hosted by: Michelle Price.

Research

Our department hosts 12 research laboratories gathering close to 200 scientists, engineers and technical staff. Research topics cover a large variety of topics, such as developmental genetics and neurogenetics, regeneration, evo-devo, physics of biology, phylogenetics or anthropology.

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Education

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contact

Department of Genetics and Evolution
Quai Ernest-Ansermet, 30
1205 Geneva
Switzerland

office: 4002A
T: +41 22 379 67 85

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