Scientists trace human blood cells back to ancient single-celled ancestors

Scientists have uncovered evidence that human blood and immune cells may have evolved from ancient single-celled organisms nearly 700 million years ago. Researchers at Kyoto University analyzed gene expression across multiple species to trace the evolutionary history of blood cells. Their findings suggest macrophages resemble early ancestral cells and that key genes like FOS originated in unicellular life. The study maps how blood cell types diversified over time, revealing deep connections between modern immunity and ancient biology.