Scientists discover common ancestor to all complex life forms

Amazing stuff! The tree of life!

".. the researchers analyzed the genomes of hundreds of archaea microbes. By winding back the molecular clock, the researchers found that all eukaryotes ... can trace their lineage to a common Asgard archaean ancestor. ...
Asgard archaea, also known as Asgard superphylum, is a group of ancient microorganisms that first appeared two billion years ago. Asgard archaea were discovered relatively recently ...
Scientists have encountered these enigmatic organisms in deep-sea sediment and hot springs across the globe, but only a limited number of strains have been successfully cultivated in laboratory settings. Asgard microbes are extremely finicky. They can't be centrifuged, stirred, exposed to oxygen, separated from other microbes, or rushed into growing any faster than a glacial pace. ..."

From the abstract:

"In the ongoing debates about eukaryogenesis—the series of evolutionary events leading to the emergence of the eukaryotic cell from prokaryotic ancestors—members of the Asgard archaea play a key part as the closest archaeal relatives of eukaryotes. However, the nature and phylogenetic identity of the last common ancestor of Asgard archaea and eukaryotes remain unresolved. Here we analyse distinct phylogenetic marker datasets of an expanded genomic sampling of Asgard archaea and evaluate competing evolutionary scenarios using state-of-the-art phylogenomic approaches. We find that eukaryotes are placed, with high confidence, as a well-nested clade within Asgard archaea and as a sister lineage to Hodarchaeales, a newly proposed order within Heimdallarchaeia. Using sophisticated gene tree and species tree reconciliation approaches, we show that analogous to the evolution of eukaryotic genomes, genome evolution in Asgard archaea involved significantly more gene duplication and fewer gene loss events compared with other archaea. Finally, we infer that the last common ancestor of Asgard archaea was probably a thermophilic chemolithotroph and that the lineage from which eukaryotes evolved adapted to mesophilic conditions and acquired the genetic potential to support a heterotrophic lifestyle. Our work provides key insights into the prokaryote-to-eukaryote transition and a platform for better understanding the emergence of cellular complexity in eukaryotic cells."

Scientists discover common ancestor to all complex life forms Scientists continue to unlock the mysteries of complex life forms through ancient genetic blueprints.

Inference and reconstruction of the heimdallarchaeial ancestry of eukaryotes (open access)

Fig. 1: Phylogenomic analysis of 15 concatenated ribosomal proteins expands Asgard archaea diversity.