a, Experimental design for fate mapping analysis of Csf1r-expressing cells. Arrows indicate analysed time points b, YFP expression on live cells from Csf1rMeriCreMer Rosa26YFP embryos pulsed at E6.5 with OH-TAM and analysed at E10.5 (n=2) and E12.5 (n=4). c, Percentage of YFP+ cells among Kit+ CD45low cells (YFP labelling efficiency) per organ/region (mean±s.e.m.). Upper panel, Csf1riCre Rosa26YFP embryos (E8.25, n=7; E8.5, n=4; E9.5, n=16; E10.25, n=9; E10.5, n=5; E11.5, n=8; E12.5, n=5); lower panel Csf1rMeriCreMer Rosa26YFP embryos pulsed at E8.5 (E9.5, n=3; E10.25, n=3; E10.5, n=4; E11.5, n=4; E12.5, n=9). e, Percentage of YFP+ cells among AA4.1+ Kit+ CD45low cells (YFP labelling efficiency) per embryonic organ/region and developmental time points (mean±s.e.m.). Upper panel, Csf1riCre Rosa26YFP embryos; lower panel: Csf1rMeriCreMer Rosa26YFP embryos pulsed at E8.5.