“An archaeal origin of eukaryotes supports only two primary domains of life” by Williams et al.
The theory, which will be further argued by Williams et al. is the one called the three-domain tree. It is the way of the biological classification, which divides the life forms into the three domains, such as archaea, bacteria, and eukaryote. This method of explaining how life has emerged, until recently, was prevalent in the molecular biology as the way classify microorganisms. James A. Lake suggested that the archaea can no longer be associated with bacteria, which both previously were believed to be united under the name of prokaryotes. Despite the fact that bacteria and archaea are sharing a lot of similarities, on the molecular level they certainly differ from one another, according to the authors. The main argument which proves that archaea have little in common with Bacteria is the way of the protein translation. Regarding the fact that there was previously hard to be sure of the archaea relation to the eukaryotes solely by the examining of the 1.8 billion years-fossils as the way of the DNA replication was damaged, the archaea seemed to have a lot in common with Bacteria and, therefore, prokaryotes (Williams et al. 231). However, the analyses conducted in the laboratory setting and the empirical studies have shown that this suggestion can be refuted. All this raises questions concerning the three-domain tree, which implies the Archaea belonging to the prokaryotes.
The primary assumption of the authors is that the correctness of the three-domain tree can be further examined, as the newly conducted experiments have shown that Archaea is like the eukaryotic structures rather than there are Archaea, Bacteria, and Eucharia, as it was previously believed. The newly developed idea of the so-called eocyte tree, which is opposed to the one that is three-domains, suggests that eukaryotes are not the “primordial cellular lineage” (Williams et al. 234), and giving both Bacteria and Archaea a decisive role in the establishing the life on Earth. The theory described above is called “the eocyte hypothesis” (Williams et al. 231), which implies that the Archaea is related to the eukaryotic nuclear lineage. The core element that seems to support the author’s idea is that there is the eocyte tree theory instead of the three-domains one, and it provides a more logical explanation of how the living form has originated from the eukaryotic cell. The improved technology of the investigations of the eukaryotic cell implied the breaking of the long branches and further investigating the smaller samples. Thankfully with this technique, the Thaumarchaeota, Aigarchaeota, and Korarchaeota were found to be related to the eocytes. Consequently, they all are the constituents of the so-called TACK Archaea (Williams et al. 234), which are sharing a lot of similarities with the eukaryotic genes and are having the same principles of functioning. The question of what has catalyzed the transition of the eukaryote to the prokaryote, which has established the various life forms, creates a complexity, which the previously developed three-domains hypothesis has failed to resolve. The eocyte tree theory suggests that the mitochondrial endosymbiont is happening within the eukaryotic organism, consequently, that the eukaryotic genes can be incorporated in the Archaea, proving that the archaeon played a significant role in eukaryotic origins. The research conducted proves that the three-domain tree system is no longer relevant can be called a breakthrough in the fieldmolecular biology. Regarding the fact that all the assumptions concerning the origin of life on Earth included the three-domain theory as a core element of their structure, one can hardly imagine the different nature of the biological classification. The advancement in the area of molecular biology has given the scientific community many abilities to be able to reject the old theories and assume that the process of the emerging of the eukaryotes from the prokaryotes can no longer rely on the Archaea-Bacteria-Eukarya, which previously had to be investigated separately as fundamentally different elements.
The research is oriented on the refutation of the theory of Carl Woese, who alongside other scientists have discovered that Archaea, Bacteria, and Eukarya are the three elements which are believed to be the constituents of the cell. As opposed to the theory described above, the eocyte tree hypothesis suggests that the fact that eocyte is put inside the Crenarchaeota, the participant of the three-domain system, is no longer relevant because the eocytes and eukaryotes are having a lot of similarities, that is, they are related. The fact that Eukarya is a part of the Archaea enables a new view on the origin of life and on the molecular biology as a whole, because it facilitates the process of the investigation of how eukaryotes has emerged from the prokaryotes, and the cellular theories, previously believed to be consistent of Bacteria, Archaea, and Eukarya as three distinct and fundamentally different from one-another elements. Regarding the fact that there is a little research made on the subject of eocyte tree in comparison to the three-domain tree, the recent findings on the issue can extend the knowledge of not only how life on Earth has originated, but of the bacteria as a genetically independent unit from archaea and, consequently, the prokaryotes. The DNA-related investigations can also now be conducted on a slightly different level: as the research on the topic of the eocyte tree, discussed above, proved that under the specific circumstances archaea’s genes could be similar to the ones of the eukaryotes, it opens up a possibility of the further DNA investigating in the field of evolutionary biology, that can affect one’s understanding of how life and, more importantly, humans were made possible by the process of transition from the prokaryotic formations to the eukaryotic cells.