A New Lineage of Eukaryotes Illuminates Early Mitochondrial Genome Reduction

The origin of eukaryotic cells represents a key transition in cellular evolution and is closely tied to outstanding questions about mitochondrial endosymbiosis [1, 2]. For example, gene-rich mitochondrial genomes are thought to be indicative of an ancient divergence, but this relies on unexamined assumptions about endosymbiont-to-host gene transfer [3-5]. Here, we characterize Ancoracysta twista, a new predatory flagellate that is not closely...