 bacteria can produce complex steroids such as cholesterol, which is essential for eukaryotic physiology. This ability was previously thought to be limited to eukaryotes, but recent research suggests that it may have evolved independently in both domains. The marine mysobacterium enhygromaxosalina was shown to produce cholesterol, and its genome revealed a pathway for its synthesis that is similar to the one used by eukaryotes. However, the bacterium uses different enzymes than those found in eukaryotes, indicating that this process evolved separately in each domain. Furthermore, the cyanobacterium calythrix sp. Mies 4105 was also found to possess the same enzyme, suggesting that this ability may be more widespread among bacteria. These findings suggest that sterile biosynthesis is much more complex than previously believed, with the potential to be shared across multiple domains.