The title is a clever reference to Dawkins' book about evolutionary fitness: The Selfish Gene (https://en.wikipedia.org/wiki/The_Selfish_Gene)
I did not follow why this is not considered some sort of virus - is it because it is not a template for any proteins, or if it is, they do not get synthesized, or they do but they don't assemble into a virus particle that encapsulates the genetic material?
best subeditor ever!
Here's the sequence of the viral-like sequence they're calling Steamer:
https://www.ncbi.nlm.nih.gov/nuccore/KF319019
We've got a bunch of similar viral-like DNA within our own genomes. And it appears some of those sequences might actually 'fight' each other over evolutionary time scales (dominant negative variants expressed from common viral-promoters) - to the point where their infighting actually is in some sense part of our own immune system's ability to ward off incoming viral sequences in favor of existing sequences we're playing host to.
Lots more biology for us to learn!