Researchers at Kyoto University have traced the origins of human blood cells to single-celled organisms that lived about 700 million years ago. Their analysis shows that modern immune cells reflect an ancient evolutionary path dating back to the emergence of multicellular animals.
The team developed a new method to compare gene expression across cell types and species. This approach allowed them to construct evolutionary trees for blood cell lineages and identify similarities with unicellular organisms. Macrophages displayed the closest links to these early ancestors, suggesting they represent the earliest form of blood cells.
