This double seminar, sponsored by the SHEETS16 program, explores a tangential but potentially exciting aspect of two-dimensional soft matter. It connects to our interest in the distinctive structures that appear when external constraints influence the shape of a 2D manifold. The compact mass of DNA that resides in the nucleus of each human cell consists of 23 pairs of DNA segments called chromosomes. This mass, called the chromatin, is strongly organized. Remarkably, the constituent chromosomes remain segregated to specific, inter-nested regions within the chromatin body. The regions have been mapped by sophisticated microscopy techniques, as shown at the top of the poster.

Recently a new statistical technique called Hi-C has enabled the two-dimensional boundaries between the chromosomes (and within them) to be examined in great detail. Fractional power laws describe the spatial correlations of these boundaries. It is not known what might be the functional or mechanical explanation for these conserved regions and the intricate interfaces that separate them.

The first seminar of the pair, by Dr. Noam Kaplan of University of Massachusetts Medical School, will introduce us to the capabilities of Hi-C and explain a new aspect of intra-chromosome structure connected to biological function.

The second seminar, by Prof. Alexander Grosberg of New York University, investigates theoretically the structure imposed on the chromatin packing coming from the intrinsic entanglement constraints of the constituent DNA polymer.

The poster shows pictorial details and abstracts of these talks

The seminar begins Monday January 11 at 1:45 in the Auditorium of Kohn hall on the UCSB campus.


T. Witten


Noam Kaplan

Encoding and decoding 3D genome organization



Alexander Grosberg

Nuclear chromodynamics


---T. Witten 18 December
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poster announcement