Fig. 9. The origins of oligodendrocytes in the embryonic rodent spinal cord. From E12.5 in the mouse, OLPs are generated from pMN in the ventral VZ. Later, from approximately E16, a subsidiary population emerges from radial glial cells in the Dbx1-expressing domain that spans the dorsoventral midline. The latter population contributes around 5% of all oligodendrocyte lineage cells in the postnatal cord. Our data do not rule out the possibility that there are additional minor sources of oligodendrocytes outside either pMN or the Dbx domain.