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merkel cells - epidermal derived cells in touch-sensitive area of the epidermis and mediate mechanotransduction in the skin. Previously thought to be neural crest in origin. Cells are named after Friedrich Sigmund Merkel, a German anatomist who was the first to describe them in 1875.

Epidermal progenitors give rise to Merkel cells during embryonic development and adult homeostasis. Van Keymeulen A, Mascre G, Youseff KK, Harel I, Michaux C, De Geest N, Szpalski C, Achouri Y, Bloch W, Hassan BA, Blanpain C. J Cell Biol. 2009 Oct 5;187(1):91-100. Epub 2009 Sep 28. PMID: 19786578 "Merkel cells (MCs) are located in the touch-sensitive area of the epidermis and mediate mechanotransduction in the skin. Whether MCs originate from embryonic epidermal or neural crest progenitors has been a matter of intense controversy since their discovery >130 yr ago. In addition, how MCs are maintained during adulthood is currently unknown. In this study, using lineage-tracing experiments, we show that MCs arise through the differentiation of epidermal progenitors during embryonic development. In adults, MCs undergo slow turnover and are replaced by cells originating from epidermal stem cells, not through the proliferation of differentiated MCs. Conditional deletion of the Atoh1/Math1 transcription factor in epidermal progenitors results in the absence of MCs in all body locations, including the whisker region. Our study demonstrates that MCs arise from the epidermis by an Atoh1-dependent mechanism and opens new avenues for study of MC functions in sensory perception, neuroendocrine signaling, and MC carcinoma."

  • Formation of epidermal and dermal Merkel cells during human fetal skin development. Moll I, Moll R, Franke WW. J Invest Dermatol. 1986 Dec;87(6):779-87. PMID: 3782861


midgut, foregut, hindgut

epiblast -> mesoderm + axial mesoderm (notochord)

lateral plate + intermediate mesoderm + somites (body), paraxial mesoderm (head) + axial mesoderm

somatic mesoderm + intraembryonic coelom + splanchnic mesoderm + intermediate mesoderm + somites (body), paraxial mesoderm (head) + axial mesoderm