Figure 4.

Aneuploid cells in the adult mouse brain. (A) Flowchart summarizing the protocol for XY FISH on isolated nuclei from embryonic and adult cerebral cortices. (B) A male lymphocyte prometaphase/metaphase spread hybridized with X (red) and Y (green) chromosome paints illustrates the specificity of these reagents. (C–E) Isolated interphase nuclei from adult male cortices were hybridized with X (red) and Y (green) chromosome paints. Nuclei were counterstained with DAPI (blue/white). Euploid male nuclei showed exactly one painted X chromosome (red) and one painted Y chromosome (green). (C) The nucleus on the right contains both an X and a Y chromosome, whereas the nucleus on the left is missing Y. (D) The nucleus in the middle is missing X, whereas the two nuclei flanking it are euploid. (E) This nucleus contains an extra Y chromosome.