In a study by the University of Nebraska-Lincoln, epigenetics was found in single-celled archaea, meaning that they are not only present in eukaryotes as previously thought. Evidence of epigenetics was found in Sulfolobus solfataricus, a sulfur-eating species that live in the boiling, acidic springs of Yellowstone National Park. Through previous studies where they increased levels of acidity through the years, scientist developed three independent and genetically different strains. These super acid-resistant derived strains were named Crenarchaeota (SARC) and they showed a resistance 178 times greater than that of their Yellowstone ancestors. This heritable acid-resistance trait was believed to be resulted from a mutation, but this later was proven to be a false assumption. By sequencing the genomes of the three strains of SARC (SARC-C, SARC-O, and SARC-I) and comparing it to the parental genome the mutations were found. SARC-C had 5 mutations and SARC-O had 29, while SARC-I had none. This implies SARC-I must have a different non-mutation mechanism. The scientists then disrupted proteins that are thought to control the expression of resistant-relevant genes and left no change in the DNA. This immediately stopped the resistance in future generations. Therefore, it can be concluded that SARC-I has an epigenetic-like mechanism.
This new evidence of Archaea having epigenetics indicates that it is not as relatively ‘new’ thing to the Earth. It also raises the question whether the shared common ancestor of Archaea and Eukaryotes had this mechanism, or did each evolve epigenetics independently through coevolution. This also raises the question if epigenetics is the reason why no known archaea cause disease or are antibiotic like bacteria. This finding could accelerate the study of epigenetics in Humans. The differentiation of eukaryotic cells and the occurrences of cancer makes it difficult to study in eukaryotes, but the simplicity of archaea and the structural similarity to eukaryotes make it easier to study. Using archaea to study epigenetics is also faster and cheaper. This may finally help scientists determine how to reverse epigenetics and learn how to switch it on and off.
https://www.eurekalert.org/pub_releases/2018-12/uon-nit113018.php
https://news.unl.edu/newsrooms/today/article/not-in-the-dna-evolution-sans-mutation-discovered-in-single-celled-archaea/
http://www.pnas.org/content/115/48/12271.full
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