Extended Data Fig. 11. Cross-species alignment of L5 glutamatergic neurons, and conservation and divergence of transcriptomic properties.

a, b, UMAP visualizations of cross-species integration of snRNA-seq data for glutamatergic neurons isolated from humans, macaques (L5 dissection only), marmosets and mice. Colours indicate species (a) or cell subclass (b). c, Heat map of cluster overlaps, showing the proportion of nuclei from within-species clusters that are mixed within the same integrated clusters. Human clusters (rows) are ordered according to the dendrogram reproduced from Fig. 1a. Macaque clusters (columns) are ordered to align with human clusters. Colour bars at the top and left indicate subclasses of within-species clusters. The blue outline denotes the L5 extratelencephalic subclass. d, UMAP visualizations of cross-species integration of L5 extratelencephalic neurons. There is good correspondence across species to the mouse L5 ET_1 subtype that projects to medulla⁵. e, Examples of cells labelled by ISH and stained with anti-SMI-32 immunofluorescence in L5 of human and mouse M1. Cells are labelled with the extratelencephalic marker POU3F1/Pou3f1 and the ion-channel genes CACNA1C/Cacna1c or KCNC2/Kcnc2. Consistent with snRNA-seq data, human L5 extratelencephalic M1 neurons appear to express higher levels of CACNA1C and KCNC2 than do mouse L5 extratelencephalic M1 neurons. Scale bars, main images, 25 μm (humans), 15 μm (mice); insets, 10 μm (humans), 5 μm (mice). f, Violin plot showing the expression of marker genes for subtypes of human L5 extratelencephalic neurons. g, Two examples of cells with Betz morphology, labelled by ISH and stained with anti-SMI-32 immunofluorescence, in L5 of human M1 that correspond to the L5 extratelencephalic clusters Exc L3-5 FEZF2 ASGR2 and EXC L5 CSN1S1. Insets show higher magnification of ISH-labelled transcripts in corresponding cells. Scale bars, 25 μm, insets 10 μm. Asterisks mark lipofuscin.