Probe:	Pax1 probe16
Probe preparation:	Antisense labelled with S35 RNA
Visualized with:	Autoradiography

Structure	Level	Pattern	Image	Note
TS15: sclerotome	Present	Regionally restricted	4B	Expression is initially more uniform and in more mature sclerotomes becomes stronger in the caudal half.
TS15: 1st branchial pouch	Present		4B
TS15: 2nd branchial pouch	Present		4B
TS15: 3rd branchial pouch	Weak		4B	Weak or undetecable expression.
TS15: hindgut	Absent		4B
TS15: tail mesenchyme	Absent		4B

Structure	Level	Pattern	Image	Note
TS17: forelimb bud	Present	Regionally restricted	4D	Expression is in the anterior proximal part of the limb.
TS17: 3rd branchial pouch	Strong		4D

Structure	Level	Pattern	Image	Note
TS19: hindlimb bud	Present		4F
TS19: nephric duct	Present		4F
TS19: head mesenchyme	Present	Regionally restricted	4F	Expression is in facial mesenchyme.

Structure	Level	Pattern	Image	Note
TS19: axial skeleton	Strong	Regionally restricted	6C	Expression is medial from the spinal nerves in the condensations that will give rise to the intervertebral discs. Lateral expression is very weak.
TS19: nephric duct	Present		6C

Structure	Level	Pattern	Image	Note
TS20: axial skeleton	Strong	Regionally restricted	6F	Expression is medially and ventromedially to the vertebral arteries and is weak lateral of the vertebral arteries.

Structure	Level	Pattern	Image	Note
TS20: trunk	Strong	Regionally restricted	6I	Expression is in the mesenchyme around the vertebral body and is absent lateral to the rib primordia.
TS20: axial skeleton	Strong	Regionally restricted	6I	Expression is in the intervertebral disc primordia.

Structure	Level	Pattern	Image	Note
TS20: tail mesenchyme	Present	Regionally restricted	6L	Expression is in sclerotome-derived mesenchyme.
TS20: tail	Present	Regionally restricted	6L	Absent in mesenchyme lateral and ventral to the tail artery and vein, or lateral to the muscle primordia.

Structure	Level	Pattern	Image	Note
TS21: knee mesenchyme	Weak	Regionally restricted	9C	Expression is at the distal end of the femur and between the tibia and fibular primordia.

Structure	Level	Pattern	Image	Note
TS22: foot	Absent		9F