Fig. 1. Immunoperoxidase staining with QCPN antibody of chick-quail chimeras sacrificed at E19-E20. Regular arrays of quail nuclei (dark brown, arrowheads) are detected in the vessel wall of blood vessels of large (A), intermediate (B) and small (C) sizes. Donor nuclei are detected in pre-capillary arterioles, adjacent the base of a feather bud (arrowhead) and inside the bud (D), as well as circulating cells in the vessel lumen (E). Quail nuclei are detected in cutaneous smooth muscle in quail-chick chimeras, as seen in longitudinal (SM-L in F) and transverse (SM-T in G) sections. (H) Hematoxylin and Eosin staining of a similar section showing morphology of bundles of smooth muscle associated with feather buds (F), immunostained for 
-smooth actin (J).
