Phylogeny-driven reconstructions of ancestral protein sequences have predicted that the last universal common ancestor (LUCA) was a thermophile, but analyses of ribosomal RNA sequences suggested that LUCA preferred a cooler environment. rRNA and protein sequences are used to show that thermotolerance initially increased from a mesophilic LUCA to thermophilic ancestors of Bacteria and Archaea–Eukaryota, and then subsequently decreased.
- Bastien Boussau
- Samuel Blanquart
- Manolo Gouy
