The influence of viruses on life on Earth, though, goes far beyond the past and present tragedies of a single species, however pressing they seem. Though the study of viruses began as an investigation into what appeared to be a strange subset of pathogens, recent research puts them at the heart of an explanation of the strategies of genes, both selfish and otherwise.
What is the subject of "both selfish and otherwise", and why is there a comma?
What does "tragedies of a single species" refer to?
article link : https://www.economist.com/leaders/2020/08/22/how-viruses-shape-the-world