Xu J, Zhu L, He SQ, Wu Y, Jin W, Qu JY, and Wen ZL (2015) “Temporal-Spatial Resolution Fate Mapping Reveals Two Distinct Origins of Microglia in Zebrafish”. Developmental Cell (In press)

 Microglia are tissue-resident macrophages that reside in the central nervous system and play critical roles in the regulation of neurogenesis and neural functions. The current prevailing view is that microglia are derived from one single source, the yolk sac (YS) in mice. A recent study ( http://www.cell.com/developmental-cell/abstract/S1534-5807(15)00552-3 ) from Drs. Wen and Qu’s groups challenges this single source view by showing that in zebrafish two distinct sources, the rostral blood island and ventral wall of dorsal aorta, give rise to microglia with different colonization potential.