Primitive Streak

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Anterior Primitive Streak

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Anterior Primitive Streak Cells

Embryonic Index: PrS.APS.APSCs

Descendants of cells labeled in the anterior streak of 4-7 somite stage mouse embryos were found predominantly in the paraxial mesoderm. Few descendants of anterior primitive streak cells were found in the endoderm and none were found in the lateral or ventral mesoderm, neither at the level of the primitive streak nor at levels further forward. This suggests that progenitor cells of the paraxial mesoderm are located in the anterior two-thirds or more of the primitive streak, while progenitor cells of the lateral mesoderm are found in the posterior third or less of the streak.