Briefly, we start with a parental ES reporter line (Dlx6a-Cre; Ai935) that fate maps subpallial neuronal lineages. The line is sequentially transcriptionally specified by Nkx2-1 and Dlx2. Nkx2-1 imparts MGE identity7,8,9 while Dlx2 further specifies GABAergic neuronal lineages36,37,38. ...