G-csf encourages myeloid differentiation, whereas Epo encourages erythroid differentiation from zebrafish hematopoietic progenitors. (A) Brightfield images (top row), mpx:eGFP fluorescence (middle row), and gata1:DsRed fluorescence (bottom row) of colonies grown in various growth factor conditions from the precursor fraction of WKM (conditions listed along top row of images). (B) Brightfield images (top row), mpx:eGFP fluorescence (middle row), and gata1:DsRed fluorescence (bottom row) of colonies grown in various growth factor conditions from the lymphoid fraction of WKM (conditions listed along top row of images). All images photographed at magnification 50×. Scale bars in top left panels are 50 μm. Arrowheads in top right panels denote mixed (CFU-granulocyte, erythroid, macrophage colonies) colonies.