Activity of Cre recombinase in Lhx6–Cre/R26R–YFP transgenic embryos and contribution of Lhx6-expressing precursors to cortical interneuron populations in the adult mouse. A–D, Expression of GFP and Lhx6 in E16.6 transgenic embryos. E, F, The contribution of Lhx6-expressing precursors to interneuron populations expressing CB, CR, PV, NPY, or SST in the motor and somatosensory cortex. The extent of colocalization between YFP and each of the five markers was quantified, and the data are presented as percentage of the total number of cells expressing each of the five markers. G, The number of Lhx6-derived cells coexpressing YFP and one of the markers CB, CR, PV, NPY, or SST are presented as a percentage of the total number of YFP+ cells. Scale bar: A, 100 μm; B–D, 20 μm.