Transplanted wild-type interneurons are correctly layered in Dab1 mutant cortex. A, Control transplantation of wild-type MGE cells (βgal⁺) into Dab1 wild-type and heterozygous hosts at E15.5 shows predominantly upper layer distribution of transplanted cells. B, Higher power of boxed area in A showing colonization of transplanted cells in upper layers. C, Histograms plotting the layer positions of transplanted cells into wild-type (n = 1) and heterozygous (n = 1) hosts (1150 βgal-positive cells; mean ± SEM percentage) showing upper layer distribution. D, Transplantation of wild-type MGE cells into Dab1 mutant ventricles at E15.5 also shows upper layer colonization of transplanted cells. E, Higher power of boxed area in D showing a similar layer distribution to the upper layers as in the control host (compare B, E). F, Histograms depicting the layer positions of transplanted wild-type cells (n = 2 animals, 490 βgal-positive cells; mean ± SEM percentage) in Dab1 mutant cortex showing that the majority of transplanted cells are situated in the upper layers. Scale bar: A, D, 290 μm; B, E, 100 μm. WM, White matter.