Three-domain system

[2][3][4] (see Two-domain system) Woese argued, on the basis of differences in 16S rRNA genes, that bacteria, archaea, and eukaryotes each arose separately from an ancestor with poorly developed genetic machinery, often called a progenote.

Prominent biologists including Salvador Luria and Ernst Mayr objected to his division of the prokaryotes.

A decade of labor-intensive oligonucleotide cataloging left him with a reputation as "a crank", and Woese would go on to be dubbed "Microbiology's Scarred Revolutionary" by a news article printed in the journal Science in 1997.

The archaeans possess unique, ancient evolutionary history for which they are considered some of the oldest species of organisms on Earth, most notably their diverse, exotic metabolisms.

Eukaryotes are the most flexible with regard to forming cooperative colonies, such as in multi-cellular organisms, including humans.

In fact, the structure of a eukaryote is likely to have derived from a joining of different cell types, forming organelles.

Parts of the three-domain theory have been challenged by scientists including Ernst Mayr, Thomas Cavalier-Smith, and Radhey S.

The associated genomes also encode an expanded repertoire of eukaryotic signature proteins that are suggestive of sophisticated membrane remodelling capabilities.