The Theory of Biological Systems lab is a research group led by Richard G. Morris. Our focus is on applying and developing concepts from statistical and theoretical soft-condensed matter physics, as well as applied mathematics, to describe biological systems. The group is part of the EMBL Australia program, and works across the departments of Physics and Single Molecule Science at the University of New South Wales (UNSW), Sydney. We are affiliated with the Australian Centre of Excellence for the Mathematical Analysis of Cellular Systems (MACSYS) and run a pan-Australia webinar series Theory Of Living Systems that aims to highlight some of the leading research in this area.
Modern life is predicated on theory and computation. The cars, planes and boats we travel in, the buildings we live and work in, and the phones and computers that we communicate with are all engineered using simulations that are based on proven theory, such as fluid mechanics, or semi-conductor physics. The overarching question that drives our research is whether we can develop such quantitative theories for living systems, so that experiment and theory might work hand-in-glove as they do in these traditional disciplines. The long-term goal is to usher in an era of integrated approaches to the study and engineering of living systems, as well as work towards the possibility of a truly in silico biology.
Evidence suggests that these changes are already underway. Across a broad spectrum of fields, the precision, fidelity, and resolution of available data only continues to improve year on year, facilitating an ever-increasing role for physical theory and computation in biology. In this context, the Morris lab is positioned at the research interface of theory and biology. Our work aims to address two ostensibly simple questions.
What can physics do for biology?
Thermodynamics, fluid mechanics, soft-condensed matter and statistical physics; these are the classical theoretical pillars that span the length- and time-scales on which biological systems operate. Part of the lab's research involves working closely with experimental partners to understand and interpret their results in the context of these disciplines. This includes work on: membrane-embedded ion channels and their conformational response to tension; Human Immunodeficiency Virus (HIV) and how its protective capsid subverts the nuclear pore complex; the scaffold protein Anillin and its unique role scaffolding cortical signalling by the small GTPase, RhoA; the role of Cadherin molecules in coupling cortical flows to enable contact inhibition, and; the role of sequence repetition in driving DNA hybridisation rates.
What can biology do for physics?
Many biological systems are poorly described by classical theories, and therefore extensions, adaptations, and even new theories must be developed. As a result, the group also works to better equip theorists with the tools needed to capture new and emergent biological behaviours, and to understand and classify biological systems according to such characteristics. Examples of this “new physics” include: the interplay between flows, morphology and local order in ordered fluid models of tissues; the non-trivial coupling between ATP, power and remodelling in actomyosin; controlling kinetics in multi-valent systems by spatial patterning of receptor sites; asymmetric motility-induced phase-separation, and; the existence of dynamical demographic phases in growing evolving populations, and how population growth alters evolution.
Tools and techniques
In terms of techniques and tools, we have so far developed, and plan to continue to develop, expertise in three broad areas:
Geometry/morphology, via the use of differential geometry and exterior calculus.
Activity, in the form of active hydrodynamics and self-propelled particle dynamics.
Fluctuations, and the effects of multiplicative and intrinsic noise.
Despite the group’s work covering an apparently diverse range of biological systems, our research program can be cast in terms of these three areas and the overlaps between them (see below).