Rare Multicellular Magnetic Bacteria Offer Clues to the Evolution of Complex Life, NASA-Supported Study Reveals

Rare magnetic bacteria, existing in tightly bound groups, are providing insights into how life may have evolved complex, multicellular forms. These bacteria, known as multicellular magnetotactic bacteria (MMB), cannot survive alone, depending on each other with each cell having a specialized role. Unlike other microbes, MMB divide as an entire group. A NASA-supported study revealed that individual cells within these groups are not genetically identical, showing surprising complexity and offering a glimpse into the early steps of life on Earth towards diverse, multicellular ecosystems. MMB are magnetotactic, using internal magnetic structures to navigate along Earth's magnetic field. They form stable, coordinated clusters of cells, showing signs of obligate multicellularity – a condition where individual cells cannot survive on their own and must live as part of the group. When MMB reproduce, they replicate all cells in the consortium at once, doubling the total number of cells, which then splits into two identical consortia. Individual cells within MMB consortia are not genetically identical and exhibit different metabolic behaviors. Each cell has a role contributing to the survival of the entire group, similar to how cells within multicellular organisms behave. For example, in human bodies, bone cells differ from blood cells, and fat cells differ from nerve cells, each with a specific function. The evolution of multicellularity is a major transition in the history of life on Earth. As the only known bacteria exhibiting obligate multicellularity, MMB provide an example of possible mechanisms behind this step in life's evolutionary history. The research was supported through the NASA Exobiology program and the Future Investigators in NASA Earth and Space Science and Technology (FINESST) program.