Origin of Life: LUCA (Introduction)

by dhw, Tuesday, March 11, 2014, 20:20 (3699 days ago) @ David Turell

DAVID: The last common ancestor of life (LUCA) is being studied in reverse style from what is now common to all life biochemistry. The assumption is that first life was one single form. Of course, that is disputed. But that form must have been as complex as life today:-"While this detailed understanding of LUCA is relatively recent, Darwin proposed the idea of an early common ancestor to all life in the first edition of Origin of Species, where he wrote, "Therefore I should infer from analogy that probably all the organic beings which have ever lived on this earth have descended from some one primordial form, into which life was first breathed." Although Darwin's insight is brilliant for its time, the modern view shows that LUCA is not this "primordial form," but rather a sophisticated cellular organism that, if alive today, would probably be difficult to distinguish from other extant bacteria or archaea. This means that a great detail of evolution must have taken place between the time of the origin of life and the appearance of LUCA. Continuing advances in evolutionary biology, bioinformatics, and computational biology will give us the tools to describe LUCA and the evolutionary transitions preceding it with unprecedented accuracy and detail. " (my bold)-http://www.the-scientist.com//?articles.view/articleNo/39210/title/Ancient-Life-in-the-...-Which raises the obvious issue: how does one get from inorganic matter and some amino acids to the complexity of LUCA?-Sorry, but this doesn't make sense to me. They want to trace evolution from the origin of life to what they call LUCA. Darwin described some "primordial form into which life was first breathed". If we descended from bacteria, and bacteria descended from whatever constituted "the origin of life", that primordial form of life ... not bacteria ... has to be LUCA. (Primordial need not mean simple. It merely denotes the earliest, original form.) So Darwin got it right. As for unprecedented accuracy and detail, how can this be possible if nobody knows the origin of life?