Organelles in cells were originally often independent cells, which were incorporated by host cells and lost their independence in the course of evolution. A team of biologists headed by Professor Dr. Eva Nowack at Heinrich Heine University Düsseldorf (HHU) are examining the way in which this assimilation process occurs and how quickly. They now describe their findings about an intermediate stage in this process in Science Advances.

Eukaryotic cells contain a large number of functional sub-units, so-called organelles. They perform important functions within the cell. Some organelles were independent, single-celled organisms at some point in the past. They were then taken up by a cell and have evolved over time in symbiosis with the host cell.

These “endosymbionts” lost their ability to function autonomously in the process. One well-known example of this type of organelle is the mitochondrion, which evolved from a bacterium.