Under the current classification system, organisms can be classified into one of three domains. describe a biological feature shared by all three domains of life that supports the concept of a common origin of life.

Under the current classification system, organisms can be classified into one of three domains, namely Archaea, Bacteria, and Eukarya. While each of the three domains have a unique set of characteristics, they also share a set of fundamental features such as an RNA polymerase, ribosomes, membrane protein insertion systems and a common genetic code, that suggest they may all have originated from a common ancestor.