All living cells power themselves by coaxing energetic electrons from one side of a membrane to the other. Membrane-based mechanisms for accomplishing this are, in a sense, as universal a feature of life as the genetic code. But unlike the genetic code, these mechanisms are not the same everywhere: The two simplest categories of cells, bacteria and archaea, have membranes and protein complexes for producing energy that are chemically and structurally dissimilar. Those differences make it hard to guess how the very first cells met their energy needs.
This mystery led Nick Lane, a professor of evolutionary biochemistry at University College London, to an unorthodox hypothesis about the origin of life. What if life arose in a geological environment where electrochemical gradients across tiny barriers occurred naturally, supporting a primitive form of metabolism while cells as we know them evolved? A place where this might be possible suggested itself: alkaline hydrothermal vents on the deep seafloor, inside highly porous rock formations that are almost like mineralized sponges.
Lane has explored this provocative idea in a variety of journal papers, and he has touched on it in some of his books, such as The Vital Question, where he wrote, “Carbon and energy metabolism are driven by proton gradients, exactly what the vents provided for free.” He describes the idea in more detail for the general public in his latest book, Transformer: The Deep Chemistry of Life and Death. In his view, metabolism is central to life, and genetic information emerges naturally from it rather than the other way around. Lane believes that the implications of this reversal touch almost every big mystery in biology, including the nature of cancer and aging. [Continue reading…]