There are fossils of viruses, of sorts, preserved in the DNA of the hosts that they've infected. Including you. This molecular fossil trail can help us understand where viruses came from, how they evolved and it can even help us tackle the biggest question of all: Are viruses alive?

Originally released by Knowledgemotion, 2018. Streaming video file encoded with permission for digital streaming by Infobase on February 21, 2020.

Where Did Viruses Come From? (8:13); .