“It’s exciting and significant to find a living family of giant viruses with eukaryote-specific genes in a form that predates the latest common ancestor of all eukaryotes,” says Albert Erives, associate professor in the Department of Biology. “These viruses are like time machines that tell us more about how life on our planet came to be.”
In the study, Erives analyzed the genome of a virus family called Marseilleviridae and found it shares a similar set of genes, called core histones, with eukaryotes.
That places Marseilleviridae, and perhaps its viral relatives, somewhere along eukaryotes’ evolutionary journey.
“We now know that eukaryotes are more closely related to viruses,” says Erives, “and the reason is because they share core histones, which are fundamental to eukaryotes.”
“So, when I saw this, it was wild,” Erives says. “No one has ever seen a virus with his tones.”
Moreover, he realized Marseilleviridae “did not get these genes from any one eukaryotic lineage living, but rather from some ancestor who was proto-eukaryotic — that is, on its way to becoming a eukaryote. Until now, no ‘organism’ was known to have core histone genes besides eukaryotic cells,” he says.
The discovery begs a larger question about the role giant viruses have played in the evolution of all life on Earth. Erives likens giant viruses to vines spreading out into the cellular tree of life — sampling here, borrowing there, and sharing genetic material among the branches of archaea, bacteria, and eukaryotes. Paper. (public access) – Albert J. Erives. Phylogenetic analysis of the core histone doublet and DNA topo II genes of Marseilleviridae: evidence of proto-eukaryotic provenance. Epigenetics & Chromatin, 2017; 10 (1) DOI: 10.1186/s13072-017-0162-0 More.
Before we get too carried away, how do we know that the genetic similarity is not better explained by horizontal gene transfer? Why not investigate that before we resort to Tree of Life claims? Or if there is a good reason for Darwinsplaining, let’s hear it.
Note: Didn’t a Marseillevirus pioneer get into trouble for doubting Darwin? There’s stuff we just daren’t think these days, no matter what the evidence or how well we are placed …
See also: Researchers ask: Do viruses share genes across the kingdoms of life?
Horizontal gene transfer: Virus carries DNA of black widow spider toxin