Thermophilic Temperature Optimum for Crenarchaeol Synthesis and Its Implication for Archaeal Evolution

The isoprenoid lipid crenarchaeol is widespread in hot springs of California and Nevada. Terrestrial and marine data together suggest a maximum relative abundance of crenarchaeol at ~40°C. This warm temperature optimum may have facilitated colonization of the ocean by (hyper)thermophilic Archaea and the major marine radiation of Crenarchaeota.