Exploring the largely unknown evolution of plasmids
Plasmids are small, usually ring-shaped, double-stranded DNA molecules that can replicate independently of their host cell. Among other things, they occur in the genetic information of bacteria, but do not belong to the bacterial chromosome. Nevertheless, as a component of the prokaryotic genome, they play an important role in the ecology and evolution of these organisms. Bacteria can, for example, use plasmids to acquire novel genetic information that can give them a selection advantage - for example, in the form of certain resistance genes from plasmids that can make their hosts resistant to antibiotics.
So far, research has mainly focused on such and similar effects that plasmids trigger in their host organisms. "However, how the genetic information of the plasmids themselves developed in the course of evolution and which molecular processes are involved is still largely unexplored," emphasises KEC board member Dagan. "In our new project, we now want to focus on the fundamentals of the evolutionary success of the plasmids themselves," Dagan continues. To this end, the researchers want to look in particular at the replication and inheritance of the plasmids in the host cells and subsequently determine which evolutionary effects are important in this process and how they affect their genome evolution. This requires an extension of classical population genetics theory to plasmid populations in bacterial cells, for which the research team wants to create new conceptual approaches to plasmid evolution from emergence to extinction.
Evolutionary perspective in research and application
The "pMolEvol" project is part of a broad spectrum of evolutionary biology research initiatives at Kiel University and its partner institutions under the umbrella of the KEC. While this project is primarily concerned with basic research, Kiel's evolutionary researchers jointly focus on a strongly application-oriented perspective. In future, this novel evolutionary perspective in research and translation should contribute to finding solutions for various contemporary societal challenges, for example in medicine, environmental protection or safeguarding food security. "Our plasmid research makes an important contribution to translational evolution research – whenever bacterial organisms are involved. This includes mainly the evolution of bacterial pathogens and how certain genetic mechanisms help them to adapt to rapidly changing environmental conditions. This makes it an important building block in countering, for example, the antibiotic crisis or other challenges caused by man-made environmental changes," Dagan summarises.