sigma neoblast PMID:29557542 PMID:28757112 Planarian_Anatomy PMID:28686611 PMID:26651295 PMID:26457503 sigma-class neoblast https://orcid.org/0000-0003-2569-1939 | https://orcid.org/0000-0002-7535-4879 PMID:25017721 PMID:25956527 PMID:27542689 PMID:28287248 PMID:27013241 A heterogeneous subpopulation of neoblasts with enriched expression of SoxP-1 and SoxP-2 thought to contain both pluripotent stem cells and tissue-specific progenitors. PMID:29906446 PMID:27150006 sigma class neoblast PMID:29674432 PMID:15972844 neoblast