An ERC Grant for mathematics applied to biology and medicine

Tracing the transmission of a gene, or modelling the reactions of certain cells to different treatments are current challenges in medicine and biology. However, the modelling of biological models presents difficulties. In particular, the size of the populations of cells studied can vary from a single cell to several thousand in a few days. Sylvie Méléard, Professor at the Centre for Applied Mathematics (CMAP*) and Member of the Institut Universitaire de France, has devoted her research to the development of mathematical models applied to biology. "What motivates me are the exchanges with biologists, to build new models and bring out new mathematical questions which will themselves lead to new biological reflections. The mathematical problems that emerge in this way are exciting and fresh," she says.

As the winner of an Advanced Grant awarded by the European Research Council (ERC), Sylvie Méléard will develop her SINGER project, which will study the stochastic dynamics of single cells. Organised in four parts, this project will take advantage of the network between biologists and mathematicians that Sylvie Méléard has built as holder of the 'Mathematical Modelling and Biodiversity' Chair.

First of all, the project will develop a model that aims to explain the presence of certain resistance genes within bacterial populations. Indeed, these particular genes are conserved in DNA fragments separated from the chromosome, called plasmids, which can be transferred from one bacterium to another by contact. Bacteria with such plasmids require additional resources to store them. It is therefore necessary to study the balance between cell demography and transfer capability and to see what behaviour this can lead to in the long term. The project will pay particular attention to a potential balance between bacteria with and without these resistance genes, or to more surprising cyclical phenomena that are difficult to capture mathematically.

Secondly, the project will establish systematic methods to characterise the lineages of individuals on an evolutionary scale. The aim is to be able to trace the evolution and transmission of a particular gene in a population over many generations, incorporating changes in the cellular environment. The third part is being developed jointly with doctors from the Hôpital Saint-Louis (AP-HP), and will model the cellular dynamics within the bone marrow. The challenges are to understand the mechanisms of invasion of cancer cells, particularly in the context of leukaemia, the appearance of resistance to chemotherapy, and the types of cells where mutations are more frequent.

The last part of the project will focus on bacteria that have been treated with antibiotics. Antibiotics mostly prevent bacteria from dividing, without necessarily killing them directly. Bacteria therefore continue to grow, forming very large and elongated cells, a phenomenon that is still poorly understood, but which is observed by new biological observation techniques known as "single cell", which are being developed in particular by a team from the University of Edinburgh that is part of the project.

This ERC funding will enable Sylvie Méléard to put together a team of young researchers to fully explore the various aspects of SINGER, with the aim of mathematically studying new models of evolution at the population level, and to deduce new long-term strategies for medical treatment.

* CMAP: a joint research unit of CNRS, École Polytechnique - Institut Polytechnique de Paris

About Sylvie Méléard:
Sylvie Méléard has been a professor at the Centre for Applied Mathematics (CMAP) at the École polytechnique since 2006 and has held the "Mathematical Modelling and Biodiversity" Chair since its founding in 2009. She leads a research team studying population dynamics and evolution with the help of her research in probability and stochastic processes. Knight of the Legion of Honour, she has supervised nearly 20 doctoral students and participated in the writing of a hundred research papers. Sylvie Méléard is therefore a leader in probabilistic modelling for biodiversity.
More information on her personal website

About the ERC Advanced Grant:
Awarded by the European Research Council (ERC), the Advanced Grants aim to support breakthrough projects that push back the frontiers of knowledge. They are awarded to established scientists on the sole basis of excellence. These grants are part of the EU's research and innovation programme, Horizon Europe.
Read more about the grants