Physics of Medicine

Research in Physics of Medicine

Macroscopic Determinism in Living Matter

Professor Alfonso Martinez Arias

I believe that Biology is the study of Living Matter and that organisms are not the result of cocktails of genes and proteins whimsically shuffled by Evolution. Instead I believe that there are constraints and Principles which determine the reproducible behaviours that we observe in the development of organisms. One question that has become important to me is derived from the realization that at the molecular (and probably at the multicellular) level, there is a lot of stochasticity in the workings of cells and yet the macroscopic level (tissues, organs, organisms) is very deterministic. How this transformation occurs is something that intrigues me very much.

My main interests lie in understanding the principles that govern the development of organisms. For some time I have felt that this is all a problem of information processing and recently I have realized that this has a framework that links it to Physics; what I am interested in are the principles which I believe exist that govern the behaviour of Living Matter. I have also come to appreciate two important gaps in the way biologists work. The first one is that we do not have a quantitative understanding of the processes we study and that much of what happens in the cell happens within a parameter range which we do not understand. The second thing is that the processes we want to understand are dynamic and can be described as emergent properties from particular sets of elements. A consequence of this realization is that in order to understand these properties and how they impinge on specific biological processes we need models, quantitative models, that describe the processes, highlight their dynamics and quantitative underpinning and make predictions. In this framework, genetics is a way to perturb the system.

The pages of my lab reflect these interests as well as highlighting our small community in which projects develop from our shared curiosity on topics of common interest. Most of the projects in the lab (hopefully all within two years) are associated with a collaboration with a physicist or an engineer. I think that this is the way forward for Biology. We have to measure, we have to model and we have to find the principles that clearly underlie the behaviour of cells when they make organisms.

We have ongoing collaborations with members of the School of physical sciences and engineering. In particular with Simon Guest on mechanical models of cell behaviour during morphogenesis, with Ben Simons on the dynamics of gene regulatory networks and lineages during development and with Jochen Guck on the mechanical properties of embryonic stem cells during differentiation.