The machinery that lets mitochondria power our cells was not a 'eukaryotic innovation' but was inherited from ancient bacteria.
April 1, 2026
Original Paper
Bacterial ancestry of the mitochondrial ATP exporter
bioRxiv · 10.64898/2026.03.31.715626
The Takeaway
For decades, the system that exports energy (ATP) from mitochondria to the rest of the cell was thought to be a unique invention of complex life. This study identified the 'missing link' in simple bacteria, proving the vital power cord of the cell was already present before complex life ever existed.
From the abstract
Mitochondria originated through endosymbiosis of an Alphaproteobacterium within an Asgard archaeal host, with ATP export to the cytosol being a key driver for the organelle integration. The mitochondrial ATP/ADP carrier (AAC), a member of the SLC25 family, performs this critical function, whose evolutionary origin was not known due to the absence of any known prokaryotic homologues and was therefore termed a eukaryotic innovation. Here, using protein tertiary structure search combined with compr