GEOapplication/xmlftp://ftp.ncbi.nlm.nih.gov/geo/series/GSE338nnn/GSE338836/primaryOK200TranscriptomicsBotryllus schlosseriExpression profiling by high throughput sequencinghttps://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE338836GEOGSEfalseMulti-stage single-cell atlas of a chordate non-embryonic development unveils dedifferentiating bud founder cellsColonial tunicates are the only chordates capable of forming fully functional bodies from somatic tissues through non-embryonic development, or budding. In Botryllus schlosseri, budding produces new individuals (zooids) from a portion of the peribranchial epithelium of a preexisting zooid. While the anatomy of this process has been described in detail, the cellular and molecular mechanisms underpinning bud initiation remain elusive. Here, we present a multi-stage single-cell transcriptomic atlas of a non-embryonic development in a chordate, capturing initiation and development of zooids. We identify an epithelial founder cell population that gains developmental potential through possible dedifferentiation, challenging the long-standing hypothesis that a long-lived, circulating pluripotent stem cell drives new zooid formation. Although some circulating cells exhibit stem-like expression profiles, these populations were either hematopoietic or germline restricted lineages. This atlas provides a foundational resource for understanding the cellular origin and mechanisms underlying agametic development and possibly whole-body regeneration in chordates.2026/07/29GSE338836GSM9883234GSM9883235GSM9883236GSM9883237GSM9883238GSM9883239GSM9883240GSM9883241GSM9883242GSM98832333722737228338836Botryllus schlosseri