The mitochondrion has long been considered to be an essential organelle for all eukaryotes, functioning as the power supply for cells. However, a recent report in Current Biology challenges this notion with the discovery of a eukaryotic organism, Monocercomonoides sp, which lacks any mitochondrial genes or proteins.
How can this eukaryote exist without mitochondria?
In this study, the authors discovered that this particular species in fact did have mitochondria at one point; however, the mitochondria were eventually lost. In its place, the microbe acquired, by lateral gene transfer, a sulfur mobilization system to replace the Fe-S cluster forming pathways. Ultimately this paper reveals how far certain eukaryotes, from underexplored environments, have adapted and evolved.
Karnkowska et al. A eukaryote without a mitochondrial organelle. Current Biology. 2016; 26(10): 1274-1284. DOI: 10.1016/j.cub.2016.03.053