Aberrant enterocyte progenitor clustering as an early life biomarker of aging.

Stem cell accumulation and mutation-derived tumors are two hallmarks of midgut aging. They imply a decline in stem cell signaling homeostasis late in life and a robust homeostasis in young adults. Contrary to this, we find spontaneously developing stem-like cells that vary in size and ploidy, have a stem-enteroblast mixed identity, achieve higher mitotic rate per cell, exhibit DNA replication stress, and are inherently prone to clustering.