Population genetics of bacteria: Dr Mario Santer receives the Otto Hahn Medal

June 12, 2024

In his research, Dr Mario Santer has made important progress in understanding the population genetics of bacteria. He has now been honoured with the prestigious Otto Hahn Medal of the Max Planck Society for his doctoral thesis. Dr Santer's work, which was carried out in the research group of Dr Hildegard Uecker, is dedicated to the genetic adaptation of bacterial populations to new environments and thus also contributes to the understanding of the evolution of antibiotic resistance.

Classical population genetics was developed for organisms that undergo meiosis and focuses on organisms with a simple (haploid) or double (diploid) set of chromosomes. The theory of population genetics for bacteria is not well developed so far. Models for the evolution of bacteria often treat them as haploid organisms. However, there are numerous types of bacteria, such as many species of cyanobacteria, that carry multiple copies of their chromosome. Additionally, many bacterial cells carry extra pieces of DNA besides the chromosome—called plasmids—that can be present in multiple copies within a cell. The spread of new gene variants thus depends not only on cell division and death but also on DNA replication within the cell and the distribution of different copies of a chromosome or plasmid to the two daughter cells (Fig. 1).

Despite their relevance to evolutionary processes, there have been few models that consider the copy number of chromosomes or plasmids. To fill this gap, Dr. Mario Santer developed fundamental theoretical models for the evolution of such polyploid bacterial populations in his dissertation. The focus of his work is on examining the probability and dynamics of genetic adaptation to changing environments.

A particular aspect of his dissertation is the comparison of theoretical predictions with experimental results, conducted in collaboration with Prof. Tal Dagan (Christian-Albrechts-University of Kiel) and her team, which impressively confirms the relevance of the models. Since resistance genes in pathogens are often located on plasmids, Dr. Santer's work is especially significant for future research in the field of antibiotic therapy.

Career Path of Dr. Mario Santer:

Dr. Santer began his academic career with a Bachelor of Science in Physics (2012-2015) and a Master of Science in Physics (2015-2018) at Christian-Albrechts-University of Kiel, Germany. From 2018 to 2022, he was a doctoral student under the supervision of Dr. Hildegard Uecker at the Max Planck Institute for Evolutionary Biology in Plön. Since 2023, he has been a member of Prof. Tal Dagan's group at the University of Kiel.

Go to Editor View