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Stochasticity Open Seminar May 29, 2017, 14:00

Open Seminars of the Research Group on


Stochasticity and Control in the Dynamics and Diversity of Immune Repertories: an Example of Multi-Cellular Co-Operation


Monday, May 29, 2017, 14:00

at the Israel Institute for Advanced Studies, Room 128



Exploratory Adaptation in Gene Regulatory Networks


Naama Brenner (Technion)


The capacity of cells and organisms to respond in a repeatable manner to challenging conditions is limited by a finite repertoire of adaptive responses. Beyond this capacity, novel and unforeseen challenges may elicit exploratory dynamics, improvisational in nature, which could provide response to a much broader array of conditions. However little is known about such exploration, its dynamics and its ability to converge to a new stable cell state.


I will review recent experiments on adaptation to unforeseen challenges. I will then describe a model of a gene regulatory network inspired by these experiments, which can converge to new adapted stable states by purely stochastic exploration. Such convergence is not guaranteed in a high-dimensional space, and indeed is not universal. Successful convergence requires outgoing hubs in the network, and is enhanced by their auto-regulation. Since these are both well-known properties of gene regulatory networks, these findings establish a basis for a biologically plausible mode of adaptation by exploratory dynamics.



Related Research Questions


  1. Gene regulation exhibits plasticity and generates novelty along evolution; how can these properties be exposed and studied in the lab?
  2. What are the characteristics and principles of exploratory dynamics resulting from this plasticity in gene regulatory networks?
  3. What allows the convergence of exploratory adaptation in the high-dimensional space of gene interactions? And how is this process related to learning?
Suggested Reading


Genome-wide transcriptional plasticity underlies cellular adaptation to novel challenge

S. Stern, T. Dror, E. Stolovicki,  N. Brenner and E. Braun

Mol. Sys. Biol. 3, article #106 (2007). See also commentary by E.V. Koonin, Mol. Sys. Biol. 3, article # 107 (2007).


Exploratory adaptation in large random networks

H. Schreier, Y. Soen and N. Brenner

Nature Communications 8, 14826 (2017). 


The unforeseen challenge: from genotype-to-phenotype in cell populations

E. Braun.

Reports on Progress in Physics, 78(3):036602, 2015.


A principle of organization which facilitates broad lamarckian-like adaptations by improvisation

Y. Soen, M. Knafo, and M. Elgart.

Biology direct, 10(1):1, 2015.



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