New Research Unveils Universal Law Explaining Chaotic Motion Of Chromosomes

Moscow, November 10, 2025

Researchers from
Skoltech, the University of Potsdam, and the Massachusetts
Institute of Technology have discovered a fundamental
physical law that governs the seemingly chaotic motion of
chromosomes inside a living cell. This discovery helps solve
a long-standing biological mystery of how two-meter long DNA
molecules, packed into dense chromosomes, remain mobile
enough for vital processes such as turning genes on and off.
The results have been published
in the Physical Review Research journal and are supported by
grants from the Russian Science Foundation (No. 25-13-00277)
and the German Alexander von Humboldt Foundation.

A
contradiction existed for a long time: On the one hand,
whole-genome analysis experiments showed that a chromosome
in the cell nucleus is packed not into a loose coil but into
a dense “fractal globule” — a compact and virtually
immobile structure. On the other hand, direct observations
of living cells demonstrated that individual sections of
chromosomes move actively and rapidly. Scientists could not
explain how such a dense globule could be so dynamic and
facilitate rapid and efficient gene regulation.

“We
developed a statistical physical model that shows that the
motion of chromosome sections, as long polymer chains, obeys
a universal physical law independent of the minute details
of their structure. The key to the solution lies in
considering not the point-like, but the collective motion of
entire DNA segments. It turns out that the ability of a gene
on a chromosome to shift as a whole (i.e., the diffusion
coefficient of its center of mass) is inversely proportional
to the number of letters in its nucleotide sequence. This is
a universal principle of polymer chains, valid both in
thermodynamic equilibrium and under cellular activity
conditions, and is fundamentally linked to Newton’s third
law,” commented the lead author of the study, Kirill
Polovnikov, Assistant Professor at the Skoltech Neuro
Center.

By analyzing two markers on a chromosome
simultaneously, the authors were able to isolate the signal
corresponding specifically to the collective motion.
Calculations showed that the collective dynamics of
chromosomes in the cell are not as fast as they appear when
observing individual points. The extracted parameter
characterizing this collective mobility was 0.77, which is
lower than predicted by the simplest model and corresponds
to theories viewing the chromosome as a compact polymer with
topological constraints — meaning DNA strands cannot
freely pass through one another, tangling into a complex
globule.

The scientists managed to resolve the
apparent contradiction. The chromosome is indeed a tightly
packed globule, but for short genomic sequences and time
intervals, its segments can behave dynamically until they
encounter the topological constraints of their own complex
structure. The model also predicts that if thermodynamic
conditions change abruptly, as happens during transitions
between cell cycle phases (including before cell division),
long-range correlations arise between segments in the
polymer chains, decaying according to the same universal
law. This effect, predicted theoretically and confirmed by
computer simulation, is a marker of the system being driven
out of equilibrium and further confirms the role of
collective motion in chromosome dynamics.

“Now, by
experimentally tracking just two reference points on a
section of a chromosome (for example, a gene), we can obtain
information about its collective dynamics and the complex
three-dimensional structure of the gene as a whole. This not
only deepens our understanding of the fundamental principles
of genome organization but also reveals the universal
physical laws governing the behavior of various polymer
systems under conditions far from equilibrium,” added
Kirill Polovnikov.

*****

Skoltech is a private
international university (part of the VEB.RF group) in
Russia, cultivating a new generation of leaders in
technology, science, and business. As a factory of
technologies, it conducts research in breakthrough fields
and promotes technological innovation to solve critical
problems that face Russia and the world. Skoltech focuses on
six priority areas: life sciences, health, and agro;
telecommunications, photonics, and quantum technologies;
artificial intelligence; advanced materials and engineering;
energy efficiency and the energy transition; and advanced
studies. Established in 2011 in collaboration with the
Massachusetts Institute of Technology (MIT), Skoltech was
listed among the world’s top 100 young universities by the
Nature Index in its both editions (2019, 2021). On
Research.com, the Institute ranks as Russian university No.
2 overall and No. 1 for genetics. In the recent SCImago
Institutions Rankings, Skoltech placed first nationwide for
computer science. Website:

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