Cells of the same age can follow sharply different biological aging paths

New research reveals that cells of the same chronological age can follow dramatically different biological aging paths, offering new insights into cancer, neurodegeneration and the fundamental biology of aging. Rather than aging uniformly, tissues become a mosaic of biologically younger and older cells, with some individual cells aging much faster than others—a discovery that could reshape how scientists understand aging and the earliest origins of age-related disease.