Mitochondria, like this one, are found inside our cells, but their ancestors would have been free-living bacteria
CNRI/SCIENCE PHOTO LIBRARY
A new study suggests that marine bacteria found in hot springs in seas and oceans may be the closest relatives to the ancient bacteria that eventually transformed into mitochondria over a billion years ago.
Mitochondria are structures found in eukaryotic cells that play a crucial role in energy production. They are believed to have evolved from alphaproteobacteria, a common group of bacteria present on Earth.
However, scientists are still uncertain about the specific bacterium responsible for this transformation, according to Otto Geiger at the National Autonomous University of Mexico.
In an effort to narrow down the possibilities, Geiger and his team analyzed the genomes of various alphaproteobacteria species to find the ones with traits most similar to the ancient bacteria that gave rise to mitochondria.
The analysis involved comparing thousands of genomes and identifying certain criteria, such as the ability to produce specific lipids essential for mitochondrial function, including ceramide.
The researchers found that marine bacteria found in hot springs, especially those belonging to the Iodidimonas genus of the Iodidimonadales order, exhibited traits most closely associated with the proto-mitochondria. These bacteria have a high dependence on oxygen, similar to mitochondria for energy production.
Geiger notes that this study is not definitive and that there may be other candidates in the future that could be even closer to the proto-mitochondria.
