Ancient Virus DNA Builds the Human Placenta?

What if part of you came from ancient viruses?

Alex Dainis explains that over 8% of the human genome is made up of viral DNA, left behind by infections from millions of years ago. These are called endogenous retroviruses (ERVs), and while many are genetic fossils with no function, some have been repurposed by our bodies for important roles. One of the most surprising? Reproduction. ERVs help form the placenta, the vital organ that connects a fetus to the uterus. Proteins from these viral genes assist in building placental tissue and turning on the genetic pathways that support pregnancy. Ancient viruses aren’t just part of your past—they help create life today.