Illuminating Cellular Individuality

Following the post-infection decision of phage lambda (L. Zeng)

We aim to reveal the origins of cellular individuality, namely, the heterogeneity in gene expression, and consequent cell-fate choices, among genetically identical cells. While it is commonly argued that cellular heterogeneity is driven by biochemical stochasticity (“noise”), we focus our attention on the possible contribution of previously uncharacterized deterministic factors (“hidden variables”) to the observed cell-to-cell variability. As long as those factors remain hidden, we are prone to interpret all cellular phenotypes as random and unpredictable. Properly identifying the deterministic drivers of cellular individuality will, instead, allow us to reveal the precision at which living cells function. The starting point for our investigation is E. coli and its virus, bacteriophage lambda. That is where we conceive of the questions and develop the methods for addressing them. In collaboration with other labs, we extend our techniques and biological pursuits to higher organisms—recently, the Drosophila embryo and mammalian stem cells.

Our studies tightly couple experiment and theory. We perform single-cell measurements of gene regulatory processes. These measurements are enabled by taking techniques originally developed for molecular visualization and converting them, using novel image analysis algorithms, into tools that allow precise counting of individual molecules and discrete events in space and time. We use coarse-grained theoretical models to motivate, design, and interpret our experiments. The theory allows us to distill our experimental results into novel biological insights. The ultimate objective, as always in physics, is to reach a narrative for cellular processes that is quantitative, simple, and universal.

Our lab is part of the Department of Physics and the Center for the Physics of Living Cells at the University of Illinois, Urbana-Champaign. We are also affiliated with the Department of Biochemistry and Molecular Biology at Baylor College of Medicine.

Following transcription in a Drosophila embryo
(H. Xu, collaboration with the Sokac lab; strain gift of H. Garcia, Berkeley)

Lab Members

Photographs courtesy of Baylor College of Medicine

Selected Publications

  For a complete list of our publications, visit  Google Scholar

Background image: Composite image showing simultaneous labeling of protein and mRNA in of E. coli (Sepúlveda et al., Science 2016),  Drosophila (Xu et al., Nature Methods 2015)
and mouse embryonic stem cells (Skinner et al., eLife 2016).

Learn more about
the Center for the Physics of Living Cells

Contact Us

Room 315 (Office) / Room 397 (Main Lab)
Loomis Laboratory of Physics
1110 W Green St., Urbana, IL 61801

Email: Ido Golding <>