Reconstructing gene content in the last common ancestor of cellular life: is it possible, should it be done, and are we making any progress?

Abstract

I review recent literature on the reconstruction of gene repertoire of the Last Universal Common Ancestor of cellular life (LUCA). The form of the phylogenetic record of cellular life on Earth is important to know in order to reconstruct any ancestral state; therefore I also discuss the emerging understanding that this record does not take the form of a tree. I argue that despite this, \"tree-thinking\" remains an essential component in evolutionary thinking and that \"pattern pluralism\" in evolutionary biology can be only epistemological, but not ontological.