Bacteria and Archaea are two of the three domains of life. Both must have evolved from the putative Last Universal Common Ancestor (LUCA). One hypothesis is that this happened because the cell membrane in LUCA was an unstable mixture of lipids. Now, scientists from the University of Groningen and Wageningen University have created such a life form with a mixed membrane and discovered it is in fact stable, refuting this hypothesis. The results will be published in the journal Proceedings of the National Academy of Sciences in the week of 19 March.
There are many ideas on how cellular life could have evolved billions of years ago. Protocells may have formed in clay minerals, or as simple lipid vesicles. In the latter scenario, something called the ‘lipid divide’ would have occurred, creating the separate domains of Bacteria and Archaea, explains University of Groningen Professor of Molecular Microbiology Arnold Driessen. ‘The lipid membranes of both domains are different, composed of phospholipids that are each other’s mirror image.’
In technical terms: the lipids in the membrane of bacteria are made up of straight-chain fatty acids
— source University of Groningen | Mar 19, 2018