Here is some more on Church's work. Work on 'de-extinction' of the Woolly Mammoth.
"Bringing Back the Woolly Mammoth Has Already Had an Unintended Consequence"
medium.com/neodotlife/de-extinction-woolly-mammoth-16c31a2dc3b3
After reading the article, I have to wonder. Did a Herpes virus against the Woolly Mammoth (like EEHV in the article) mutate to a state which eradicated both the Woolly Mammoth AND the virus itself? We think of Herpes viruses being just dangerous enough to not kill the host. But what if some gene mutations do just that?
That situation puts a whole new light on what past extinctions can be. That species aren't necessarily killed off by other predators/environmental conditions. That mutations of Herpes viruses alone are sufficient to cause extinction. How long did the Mammoth roam the earth before a Herpes virus mutation destroyed the species? 400,000 years?