Our DNA holds evidence of a huge, ancient pandemic, one that touched many different species, spanned the globe, and lasted for more than 15 million years.

The paper we discuss throughout the episode:
Diehl, W., Patel, N., Halm, K. and Johnson, W., 2016. Tracking interspecies transmission and long-term evolution of an ancient retrovirus using the genomes of modern mammals. eLife, 5.
https://elifesciences.org/articles/12704​

Produced in collaboration with PBS Digital Studios: http://youtube.com/pbsdigitalstudios​