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Around eight per cent of your DNA was left behind by ancient viruses, and one of those stolen viral genes is what builds the placenta — meaning every mammal alive, including you, was born because a vi
Space Daily • • general
Key Points:
- Approximately 8% of the human genome consists of sequences from ancient retroviruses, which integrated into our DNA millions of years ago and have been inherited like any other genetic trait.
- One such viral gene, called syncytin, was repurposed during mammalian evolution to help form the placenta by enabling the fusion of cells, allowing nutrient and oxygen exchange between mother and fetus without mixing their blood.
- This viral-derived protein also plays a crucial role in preventing the maternal immune system from rejecting the fetus, which is genetically distinct from the mother.
- Different mammalian lineages independently captured and utilized distinct viral genes to develop their placentas, demonstrating convergent evolution using viral "spare parts."
- The author reflects on the profound and humbling connection between ancient viral infections and human pregnancy, highlighting how inherited viral genes continue to play vital roles in biology today.
