[3] Sediments from a gravity core taken in 2010 in the rift valley on the Knipovich ridge in the Arctic Ocean, near the so-called Loki's Castle hydrothermal vent site, were analysed.

[6] The Loki of literature has been described as "a staggeringly complex, confusing, and ambivalent figure who has been the catalyst of countless unresolved scholarly controversies",[8] a coincidental analogy to the role of Lokiarchaeota in debates about the origin of eukaryotes.

This situation is consistent with: (i) proteins from a novel phylum (with few close relatives, or none) being difficult to assign to their correct domain; and (ii) existing research that suggests there has been significant inter-domain gene transfer between bacteria and Archaea.

Homologues for components of the endosomal sorting complex required for transport and the ubiquitin protein modifier system were also identified in Lokiarchaeota genome analysis.

[3] The presence of actin proteins and intracellular transport mechanisms provides evidence for the common ancestry between ancient Lokiarchaeota and eukarya.

The bacteria and archaea are thought to be the most ancient of lineages,[21] as fossil strata bearing the chemical signature of archaeal lipids have been dated back to 3.8 billion years ago.

[23] While the evolution of eukaryotes is considered to be an event of great evolutionary significance, no intermediate forms or "missing links" had been discovered previously.

Evidence for common ancestry, rather than an evolutionary shift from Lokiarchaeota to eukaryotes, is found in analysis of fold superfamilies (FSFs).

[11] Utilization of Venn diagrams allowed researchers to depict distributions of FSFs of those that were shared by Archaea and Eukarya, as well as those unique to their respective kingdoms.

Lokiarchaeota’s limited impact in changing the Venn distribution of FSFs demonstrates the lack of genes that could be traced to a common ancestor with Eukaryotes.

While association with alphaproteobacteria (from which mitochondria are thought to descend) was not observed, these features suggest that MK-D1 and its syntrophs may represent an extant example of archaea-bacteria symbiosis similar to that which gave rise to eukaryotes.

[2] Analysis of Lokiarchaeon genes also showed the expression of protein-encoding open reading frames (ORFs) involving the metabolism of sugars and proteins.

While Lokiarchaeota subgroups have similar genetic information, differences in metabolic abilities explain their respective ecological niches.

Incubations of these two subgroups from Helgoland mud sediments were analyzed through RNA and DNA stable isotope probing to understand their respective carbon metabolisms.