Multiple approaches of cellular metabolism define the bacterial ancestry of mitochondria

We breathe at the molecular level when mitochondria in our cells consume oxygen to extract energy from nutrients. Mitochondria are characteristic cellular organelles that derive from aerobic bacteria and carry out oxidative phosphorylation and other key metabolic pathways in eukaryotic cells. The precise bacterial origin of mitochondria and, consequently, the ancestry of the aerobic metabolism of our cells remain controversial despite the vast genomic information that is now available. Here, we use multiple approaches to define the most likely living relatives of the ancestral bacteria from which mitochondria originated. These bacteria live in marine environments and exhibit the highest frequency of aerobic traits and genes for the metabolism of fundamental lipids that are present in the membranes of eukaryotes, sphingolipids, and cardiolipin.

Automated summary

We breathe by using oxygen consumed by mitochondria in our cells to extract energy. Mitochondria, which derive from aerobic bacteria, play crucial roles in oxidative phosphorylation and other metabolic pathways in eukaryotic cells. The exact bacterial origin of mitochondria and their relationship to the aerobic metabolism of our cells is still controversial despite the abundance of genomic data. In this study, we employ various approaches to identify the most likely bacteria that are the living relatives of the ancestral bacteria from which mitochondria originated. These bacteria inhabit marine environments and possess a high frequency of aerobic traits as well as genes for the metabolism of essential lipids found in eukaryotic membranes, such as sphingolipids and cardiolipin.