Fourth after archaea, bacteria, and eukaryotes (multicell).
Here’s the story of a new virus discovery from Nature:
Each is around 1 micrometre long and 0.5 micrometres across, and their respective genomes top out at 1.9 million and 2.5 million bases — making the viruses larger than many bacteria and even some eukaryotic cells.
But these viruses, described today in Science1, are more than mere record-breakers — they also hint at unknown parts of the tree of life. Just 7% of their genes match those in existing databases. Bl21“What the hell is going on with the other genes?” asks Claverie. “This opens a Pandora’s box. What kinds of discoveries are going to come from studying the contents?” The researchers call these giants Pandoraviruses. More.
One possibility is that there were once many more domains of life. Another is that domains of life are neither organized nor separated in quite the ways that orthodoxy insists on today. Or both of these possibilities at once.
We’ve talked about giant viruses here before, for example:
The French vs. Darwinism
Mimivirus discoverer doubts Darwin, banned from publication in France
Megavirus has largest currently known genome, mimics cell genome
See also: New Nature paper challenges conventional boundaries between kingdoms of life
Not to worry: Darwin’s followers can catch up once they can find some way that Darwin predicted all this.