How your blood formed? Scientists say ancient 700-million-year-old single-celled ancestors may still live inside human blood

Scientists discover ancient single-celled ancestors still live on in human blood, revealing a 700-million-year evolutionary link hidden inside the immune system. Researchers at Kyoto University traced modern blood cells back to primitive unicellular organisms that existed before complex animals appeared on Earth. The study found macrophages and immune genes like FOS still carry ancient biological patterns today.