Kyoto University Traces Blood Cells to 700-Million-Year-Old Single-Celled Ancestors
Updated
Updated · SciTechDaily · May 31
Kyoto University Traces Blood Cells to 700-Million-Year-Old Single-Celled Ancestors
3 articles · Updated · SciTechDaily · May 31
A new Kyoto University analysis found modern blood and immune cells retain genetic programs from unicellular ancestors dating back about 700 million years, pushing their origins to the dawn of multicellular animals.
Researchers reached that conclusion by comparing gene activity across species and cell types, then building evolutionary family trees that included unicellular organisms as well as animals.
Macrophages showed the strongest similarity to single-celled life, suggesting the earliest blood cells were macrophage-like; the widely used blood-cell gene FOS was also traced to a unicellular ancestor.
The reconstructed lineage suggests mast cells later split from macrophages, with prototypic T cells and red blood cells emerging from mast cells, while prototypic B cells branched from macrophages.
The team said the method could also help trace the evolutionary roots of diseases including cancer, potentially sharpening understanding of disease mechanisms and treatment targets.
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700 Million Years in Our Veins: Kyoto University Maps the Evolutionary Origins of Human Blood and Immunity
Overview
A groundbreaking study from Kyoto University, published on May 29, 2026, has traced the origins of human blood back about 700 million years to early single-celled organisms. This research reveals that the first blood cells likely resembled macrophages—immune cells that protect the body by engulfing harmful microbes and debris. By comparing gene activity across species, scientists found that macrophages share strong similarities with unicellular ancestors. These findings provide a comprehensive view of how blood and immune cells first appeared and diversified, fundamentally changing our understanding of their evolution and highlighting our deep biological connection to ancient life.