Recently, Prof. Meng Li'group from the Institute for Advanced Study at Shenzhen University published a research article in theNature Communications, making a breakthrough in research on archaea evolution and eukaryogenesis. This work sheds light on evolution of optimal growth temperature (OGT) in Asgard archaea and proposed that archaeal ancestor of eukaryotes had an OGT around 53 °C. The Prof. Li is the corresponding author, and the first authors are Zhongyi Lu and Runyue Xia.

Eukaryogenesis has been a long-standing puzzle in biology. Current mainstream thinkings believe that eukaryotes evolved from symbiosis fusion between specific archaeal ancestors and α-proteobacterial ancestors. The specific archaeal ancestor likely evolved from Asgard archaea. Thus, exploring the evolution of Asgard OGT can provide clue of the temperature regime of eukaryogenesis.

This work phylogenetically characterized elongation factor 1A (EF-1A) of Asgard archaea, and accordingly reconstructed their ancestral proteins. Further measuring optimal GDP-binding temperatures of these Asgard EF-1A and ancestral proteins indicates a gradual decrease of OGT during Asgard evolution (Figure 1). In addition, this work suggests that the Asgard ancestor of eukaryotes was a moderate thermophile, with an optimal growth temperature around 53°C.

This work was supported by the Natural Science Foundation of China (32225003，32393970，32393971，92251306，32370004), Guangdong Basic and Applied Basic Research Foundation (2023A1515011309) and Shenzhen University 2035 Program for Excellent Research (2022B002). Link to the article:https://doi.org/10.1038/s41467-024-44806-1。

Figure 1 Evolution of optimal growth temperature in Asgard archaea