Kim Sneppen, Simons Center Talk: “We are basically all doughnuts”

Kim Sneppen

Over the last several days (December 3-7) the Simons Center for Geometry and Physics at Stony Brook University has been hosting a series of lectures on Nonequilibrium Physics in Biology and streaming the video talks over the Internet.

Stony Brook is where philanthropist Jim Simons taught math for a decade before starting his enormously successful hedge fund—and with his wife Marilyn, the Simons Foundation, which is now at the forefront of a revolution in science.

This week’s Simons Center talks on nonequilibrium physics in biology are also permanently linked as videos.  It helps to know some fancy math in viewing them, but many of the presentations rely more on speaker charisma and images to drive home the salient points.

Among the more interesting presenters is Kim Sneppen, a professor of complex systems and biophysics at Neils Bohr Institute in Copenhagen, who addresses the diversity of shapes in the biological world. 

Sneppen says, “We are basically all doughnuts” and describes how we go from a sphere to a torus in his talk titled: “Theoretical Tool Bridging Cell Polarities with Development of Morphologies.” 

I once asked physicist Leonard Susskind about this concept since he’d co-authored a paper on “the incredibly shrinking torus,” but Susskind told me he had “NO IDEA how the torus enters biology” and that everything he knew about evolution he’d learned from reading Richard Dawkins’ book.

The concept is one Stuart Pivar‘s been thinking about for quite some time.

Here’s a link to the Sneppen Simons Center video:

Last year Sneppen was awarded DKK 16.5M (US$2.5M) by the European Research Council to “explore the diverse and complex world within and between cells.” 

In relation to his ERC grant, Sneppen said the following:


“I want to initiate a new research direction at the research frontier between biology and physics.  By its diversity of molecules, interactions and cells, biology expresses its universality in different forms than found in systems conventionally explored by statistical physics. . . .I describe biological systems with focus on the rules of interactions and their consequences rather than dig down into the smallest details.”

In discussing the diversity of shapes in his Simons Center talk, Sneppen emphasizes that it’s most effective to “work close to the scale of the phenomenon.”

I had the pleasure of meeting Kim Sneppen several years ago in Copenhagen during ICSB2013, the International Conference on Systems Biology.  It was September and Sneppen was wearing bermuda shorts and an oxford shirt—sleeves rolled up.  He’s an attractive man with Nordic blue eyes dramatically framed by unruly brows. 

At one point in his Simons Center talk he informs the audience about the way hair grows perpendicular to skin, although Sneppen’s own brows are very clearly in defiance!

In much of the lecture Sneppen discusses how cells make sheets and tubes.  He notes that cells have proteins on the outside that enable them to stick together.  But that by putting an organizing force on the polarity vectors, shape can change.

Sneppen identifies several rules for embryonic development:  (1) polarity, (2) signaling, (3) differential adhesion, (4) apoptosis.    

The strength of planar cell polarity (PCP) he says is associated with tube formation and that the strength of PCP controls tube length and width. He also says PCP drives gastrulation and neurulation

Sneppen announced recent publication of his paper: “Theoretical tool bridging cell polarities with development of robust morphologies.”

Other talks of interest include Joe Howard’s on what’s responsible for cell oscillations: “Oscillatory enthalpic changes during early embryogenesis driven by the cell cycle.”  And Jacques Prost’s “Tissues as Active Systems” (serious math involved).

December 7 is the last day of the workshop but, again, the Simons Center video talks remain posted for future viewing.

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