# Martijn de Jong – The maths behind a biological process

Bachelor’ student mathematics and physics Martijn de Jong used mathematics to unravel a complex biological process called gastrulation. He combined various scientific disciplines. ‘It is nice to work at the interface between different fields.’

## Mathematics or physics?

‘I have always been fascinated by special physical phenomena and how they work exactly,’ De Jong explains his initial choice for the bachelor's in physics. He finally decided to study mathematics too, because he became interested in the mathematical background of physics. And it suited him well: ‘During my studies, I increasingly appreciated the broad possibilities of mathematics, which is why I eventually opted for the master’s Applied Mathematics in Leiden.’

## From cell to model

For his bachelor's research, De Jong conducted thorough research into a crucial phase of embryonic development: gastrulation. In this phase, the embryo grows from a hollow sphere of single-layered cells into a multi-layered structure called gastrula. At the end of this process, so-called differentiation begins, whereby different types of cells are created. ‘These cells then form different tissues, greatly varying in shape. For example, they can be round, or oval, or elliptical. During my research I tried to model this variation with a mathematical model.’

‘I am fascinated by physical phenomena and how they work. During my bachelor I used both mathematics and physics to chart a crucial phase of embryonic development.’

And De Jong is pretty successful at it. He managed to expand a simple existing model that describes how cells attract each other. ‘The results of this model, such as variation in shape, therefore more closely resemble the variation that we actually observe.’ De Jong was able to see this through a new technique to compare the shape of simulated and observed tissues. ‘I have also succeeded in improving the algorithm needed to create the simulations. As a result, calculations can be performed much faster in many cases.’

## Multi-disciplinary

With his research, De Jong not only contributed to more knowledge about this specific process but also to more knowledge about sorting cells and stretching tissue in general. De Jong: ‘Since this plays an important role in many biological processes, knowledge about this is always useful, for example in medical biology.’

De Jong also shows that combining scientific disciplines can offer new insights in various areas. ‘Mathematics and physics, as well as biology and computer science, have played a role in my research. This has led to insights at the interface between these disciplines.’