A radical new study, published in Science Advances, suggests that this unlikely threshold may actually have been crossed not once, but twice. "Let's call it by name: we are looking at one origin of the genetic code, but two origins of life." Enzymes themselves are products of chemical reactions – so how did the first lifeforms begin metabolizing things, including making enzymes, without the help of other enzymes? "Such parallel inventions could have paved the way to the independent emergence of free-living bacteria and archaea." Yet critical to chemical reactions is the medium in which they occur, and scientists still don't have a clear idea about that.