Do you think your DNA is entirely human? Because if you do, you might need to reconsider, since a group of scientists have recently discovered that our DNA is less human than previously anticipated. Here are the amazing facts:

Nineteen new pieces of “alien” DNA have just been discovered hiding out between our own genes. The non-human DNA is thought to originate from viruses that once infected our ancestors hundreds of thousands of years ago.

After conducting a study on 2,500 people from across the world, researchers discovered that 50 of them possessed a small portion of the newfound DNA which in term had a complete genetic recipe for an entire virus. Besides these newly discovered stretches of DNA, the researchers also confirmed 17 other pieces of virus DNA found in human genomes by other scientists in recent years. The study has been performed using sophisticated techniques which allowed for key areas of each person’s genome to be compared to the “reference” human genome.

Many studies have tried to link these endogenous viral elements to cancer and other diseases, but a major difficulty has been that we haven’t actually found all of them yet,” said co-author of the study, Zachary H. Williams. “A lot of the most interesting elements are only found in a small percentage of people, which means you have to screen a large number of people to find them.


The human endogenous retroviruses, or HERVs, is the name given to the ancient infectious viruses that integrated a DNA-based copy of their own RNA genetic material into our ancestor’s genomes. The team of researchers is now trying to figure out whether or not it can replicate, since other studies of ancient viruses DNA have revealed that it can affect the humans who carry it.

The stretches of DNA generated by the virus kept getting copied from generation to generation whenever humans reproduced. This doesn’t show however if the virus can replicate by itself, but it highlights the fact that it got carried over hundreds of thousands of years inside the human DNA. Intriguingly enough, about 8 percent of what we consider to be “human” DNA comes in fact from ancient viruses. In some cases, HERV sequences have been adopted by the human body to serve a beneficent purpose, such as one that helps pregnant women’s bodies build a cell layer around a developing fetus to shield it from toxins present in the mother’s blood.

This is a thrilling discovery,” said co-author of the study, Julia Wildschutte. “It will open up many doors to research. What’s more, we have confirmed in a paper that we can use genomic data from multiple individuals compared to the reference human genome to detect new HERVs. But this has also shown us that some people carry insertions that we can’t map back to the reference.

It appears that 8 percent of our human DNA actually comes from ancient viruses. The fact that our bodies copied some traits from these viruses along the years and integrated them into our systems points out at the complexity of the human nature. (source)

The findings are published in Proceedings of the National Academy of Sciences.