[3] Its discovery in the 1970s was the main starting point of research on yeast virology.

[4] It is a ~4.6 kb double-stranded RNA virus with no extracellular phase and so is inherited through vertical cytoplasmic transmission.

A yeast lineage with a M/killer virus is known as a "killer strain".

[5] There are numerous apparently unrelated M dsRNAs that use L-A, their only similarity being their genome organization.

The family of Totiviridae in general helps M-type dsRNAs in a wide variety of yeasts.