How did cholesterol evolve? Oil trapped in ancient rocks hides clues
Ancient life forms may have left traces of oily molecules in rocks more than 1 billion years ago, providing new insights into the evolution of cholesterol. The molecular fossils, described today in Nature , suggest early organisms that relied on precursors of cholesterol were widespread on ancient Earth. Later, rising levels of oxygen allowed organisms to make the more sophisticated version of the molecule we know—and sometimes hate—today. Cholesterol gets a bad rap for its role in heart disease, but animal cells can’t live without it. Our cell membranes are roughly 30% cholesterol; the molecule keeps membranes flexible over a range of temperatures and plays a key role in receiving signals from other cells. Cholesterol belongs to a family of similar molecules called sterols. Animal cells make...