RESUMEN
Adult tissues are known to contain rare populations of stem cells with multilineage differentiation potential that are distinct from other resident tissue-specific stem cells. However, whether multilineage stem cells are involved in tissue development is uncertain, primarily because the identification and characterization of these cells in embryonic tissue primordia is not well established. We tested whether stem cells with multilineage potential are present within the early post-gastrula somite tissue. We show that clonally derived precursor cells generate colonies with self-renewal capacity and have both neurogenic and myogenic lineage potential. Somite colonies contain cells that express Sox2, nestin, and Sca1, but do not express genes indicative of somitic mesoderm specification. Furthermore, we demonstrate that this multilineage potential is not due to colony cells with a pluripotent epiblast identity or the selection of p75 receptor-positive neural crest stem cells. Despite utilizing a highly undifferentiated tissue source, colony formation was not enhanced relative to reported estimates of multilineage stem cells from adult muscle, a derivative of the embryonic somite. Thus, our findings suggest that a permissive in vitro environment is sufficient for the isolation of a discrete population of stem cells in the embryonic somite that may represent the earliest developmental precursor to adult muscle multilineage stem cells.