Post 2: Mom… I’m an archaeon! 🦠

One of the current gaps in biology is how we went from being a prokaryote to a eukaryote. Around the 1970s-1980s, it was known that there was a third group of organisms just as old as bacteria, but they weren’t bacteria, so they were called Archaea, because they’re just as old.

In 2015, several genomes of marine archaea were recovered that are believed to be the missing link between prokaryotes and eukaryotes, and they were called Asgardian archaea (Loki, Hel, Thor, Odin, and Heimdall, with the latter group believed to be the ancestors of eukaryotes). The deal with these organisms is that they have a highly reduced genome and had never been able to be cultivated because they only live if they are associated with their symbiotic hosts… until now.

(Even though the article is still in preprint on Biorxiv) In August of this year, a team of 100 Japanese researchers led by Ken Takai published the first isolation of one of these Asgardian archaea from the Lokiarchaeota group, which took more than 12 years to ensure that the darn culture wasn’t contaminated and grew enough to be isolated and sequenced, as it doesn’t grow alone, it grows together with methanogenic bacteria like Halodesulfovibrio and Methanogenium.

The organism in question was named Prometheoarchaeum syntrophicum and experimentally demonstrates much of the reduced metabolism of these organisms that was only known through bioinformatic methods

Refs:

Isolation of an archaeon at the prokaryote-eukaryote interface