Antibody:	anti-Sox9
Detection system:	Biotinylated secondary antibody/[Strept]avidin coupled to horseradish peroxidase

Structure	Level	Pattern	Image	Note
TS17: notochord	Present		4A
TS17: sclerotome	Present		4A
TS17: future spinal cord	Present	Regionally restricted	4A	Expression was detected in the ventricular neuroepithelial layer of the spinal cord.

Structure	Level	Pattern	Image	Note
TS21: notochord	Present		4B
TS21: vertebral pre-cartilage condensation	Present		4B
TS21: dorsal root ganglion	Absent		4B
TS21: laryngeal cartilage	Present	Regionally restricted	4B	Expression was in the mesenchymal condensations of the laryngeal cartilages.

Structure	Level	Pattern	Image	Note
TS21: vertebral pre-cartilage condensation	Present	Regionally restricted	4C	Expression was detected in the vertebral bodies undergoing chondrocytic differentiation, but not yet hypertrophy.

Structure	Level	Pattern	Image	Note
TS25: hindlimb skeleton	Strong	Regionally restricted	4D	Expression was strong in the proliferating chondrocytes of a hindlimb bone.

Structure	Level	Pattern	Image	Note
TS25: hindlimb skeleton	Present	Regionally restricted	4E	Expression was strong in proliferating chondrocytes, but is downregulated in hypertrophic chondrocytes.

Structure	Level	Pattern	Image	Note
TS17: otocyst epithelium	Present		4F

Structure	Level	Pattern	Image	Note
TS17: endocardial cushion	Present	Regionally restricted	4G	Expression was detected in the endocardial cushions flanking the atrioventricular canal.
TS17: cardiac muscle tissue	Absent		4G	Expression was absent from epimyocardium.