The quest for life’s blueprint

All modern organisms have DNA, all of which, again, contain genes. Without the genes, an organism would have no way to pass anything on to its offspring.

Even worse, without DNA-based genes, there is no way to create proteins, which are fundamental to any living form. Some viruses have RNA instead of DNA, but these viruses nonetheless still have genes.

However, there surely was a time when our ancestors did not have both DNA and RNA. All life arose from some kind of chemical soup that existed in lakes, in the ocean or in hot springs. Whatever the first form of life was, it may not have possessed anything we would recognize as genes.

This chart depicts some possibilities. It is an evolutionary tree with life beginning at the point indicated as LUCA, i.e. Last Universal Common Ancestor.

Perhaps life arose from clay particles that could somehow act as templates for replication. Or as bubble-like membranes that have been shown to be able to replicate without genes in lab experiments. Another possibility is that life could have originated from chemical reactions inside thermal vents on the ocean floor, as shown in the picture below.