Matters arising: Insufficient evidence that pancreatic β cells are derived from adult ductal Neurog3-expressing progenitors

Newswise — Magenheim et al. challenge a recent study claiming that pancreatic beta cells are generated at a physiologically important rate from progenitor cells within ducts. They show that the lineage-tracing systems used in that study do in fact pulse label islet cells, precluding conclusions about duct cells giving rise to islet cells.