Are We Part-Human/Part-Virus?

Our genome is not entirely made up of human genes, there are roughly 100,00 pieces of viral DNA in our genome. This constitutes 8% of our entire genome. This past July, scientist found a protein called Hemo in the veins of pregnant women. What was more surprising was that this protein is not made by the mother, but in the fetus in the placenta. Hemo is made from a viral gene that infected our mammalian ancestors more than 100 years ago.

DNA viral genes in humans can be good and bad. While some can help defend us from disease, others increase our risk for diseases like cancer by through activating cells to switch on other genes. Others like, Dr. Coffin, a virologist from Tufts University, argue that viral DNA has played a vital role in human evolution as some viral proteins aid in reproduction. For instance, syncytins are made from viral DNA and fuse placenta cells together, which is necessary part of normal fetal development.  

There are many hypotheses on the significance of Hemo. Some experiments suggest that this protein helps the embryo develop different tissues. Researchers like Dr. Odile Heidmann from the Paris cancer research institute, suggests that Hemo proteins are the fetus’s message to the mother from the fetus to prevent the mother’s immune system from attacking it. Others suggests that viruses like Hemo may have exploited embryos to make more copies of themselves.

-Jessica Ngo

Source: https://www.nytimes.com/2017/10/04/science/ancient-viruses-dna-genome.html