Cecilie Bækkedal Sonnenberg

Bacteria are found widespread in almost every habitat on Earth, from deep seas to the clouds. While most bacteria have all their genes on one circular DNA molecule, about 10% of bacteria have their genes spread out over two or more DNA molecules. These are called multipartite bacteria and they are particularly interesting because many of them live on other organisms, such as corals, fish, plants and humans. They can either provide benefits or cause disease. The presence of multiple DNA molecules is believed to provide advantages to multipartite bacteria, and this study aimed to investigate why some bacteria have multiple DNA molecules.

This study focused on the marine bacteria Vibrionaceae and Pseudoalteromonas, which have two DNA molecules. It revealed that different types of genes are located in separate areas on the DNA molecules. Genes responsible for growth and survival are placed in one half of the circular DNA molecule, while genes important for adaptation to new environments and coexistence with other organisms are located on the remaining areas of the DNA molecules.

Overall, this study offers new insights into why some bacteria possess multiple DNA molecules and how the different gene types are arranged on these molecules.