Probe:	Pax1 probe3
Probe preparation:	Antisense labelled with digoxigenin RNA

Structure	Level	Pattern	Image	Note
TS12: embryo	Present		3A	Onset of expression at 8.25 days p.c. (up to 7 somites)
TS12: somite	Present	Regionally restricted	3A	Expression in ventromedial portions of anteriormost somites just before de-epithelialisation; no expression in youngest 3-4 somites.
TS12: branchial pouch	Present		3A

Structure	Level	Pattern	Image	Note
TS16: trunk somite	Present	Regionally restricted		Expression in lumbar region.

Structure	Level	Pattern	Image	Note
TS17: head mesenchyme	Present		3B	Anteriormost expression in head mesoderm
TS17: head	Present	Regionally restricted	3B	Expression at base of skull.
TS17: trunk somite	Present	Regionally restricted	3B	Expression in lower sacral/upper caudal regions.
TS17: sclerotome	Present		3B	Axial expression restricted to sclerotomal part of somites.
TS17: branchial pouch	Present		3B
TS17: forelimb bud	Present		3B

Structure	Level	Pattern	Image	Note
TS19: tail somite	Present	Regionally restricted		Expression in 37 out of 39 trunk and tail segments.
TS19: trunk somite	Present	Regionally restricted		Expression in 37 out of 39 trunk and tail segments.
TS19: hindlimb bud	Present
TS19: head	Present	Scattered		Authors report expression in the face.

Structure	Level	Pattern	Image	Note
TS20: tail somite	Present	Regionally restricted	3C	Expression in 44 out of 45 trunk and tail segments.
TS20: sclerotome	Present		3C	Axial expression restricted to sclerotomal part of somites.
TS20: hindlimb	Present		3C
TS20: head	Present	Regionally restricted	3C	Authors report expression in the face.

Structure	Level	Pattern	Image	Note
TS15: trunk somite	Present	Regionally restricted	4A left	Expression in 19 out of 22 somites.
TS15: branchial pouch	Present		4A left

Structure	Level	Pattern	Image	Note
TS15: embryo	Present	Regionally restricted	4A right	Though no distinct somites are visible, up to 3 paired domains beside the neural tube. Single island of expression posterior to pericardium.

Structure	Level	Pattern	Image	Note
TS17: embryo	Ambiguous			Authors report that 4 embryos were analysed, two of which showed no expression.

Structure	Level	Pattern	Image	Note
TS18: forelimb bud	Present	Regionally restricted	4D	Expression in one patch of paraxial mesoderm and the dorsally shifted forelimb bud.
TS18: paraxial mesenchyme	Present	Regionally restricted	4D	Expression in one patch of paraxial mesoderm and the dorsally shifted forelimb bud.

Structure	Level	Pattern	Image	Note
TS17: trunk somite	Present	Regionally restricted	4E	Termination of expression posterior to hindlimb bud. Less intense expression in 2-5 posterior-most segments lacking ventral portion.

Structure	Level	Pattern	Image	Note
TS19: trunk somite	Present	Regionally restricted	4F	Termination of expression posterior to hindlimb bud. Expression in 29 of 38 trunk and tail body segments.

Structure	Level	Pattern	Image	Note
TS20: tail somite	Present	Regionally restricted		Expression in 28 of 40 trunk and tail segments.

Structure	Level	Pattern	Image	Note
TS17: trunk somite	Present	Regionally restricted	5A	Expression terminated at level of hindlimb bud; expression in the last 3-6 segments appearing less intense and lacking the medial portion.

Structure	Level	Pattern	Image	Note
TS20: somite	Present	Regionally restricted	5B	Expression terminated anterior to hindlimb bud, at the 20th-21st body segment.

Structure	Level	Pattern	Image	Note
TS20: trunk	Weak	Regionally restricted	5C	Expression in trunk declining in anterior region of tail.

Structure	Level	Pattern	Image	Note
TS17: trunk somite	Present	Regionally restricted	6A	Termination of expression posterior to hindlimb bud. Expression in 29 out of 32 body segments; weak or no expression in up to 7 terminal seqments.

Structure	Level	Pattern	Image	Note
TS20: somite	Present	Regionally restricted	6B	Expression only in the anterior 38 body segments; no expression in about the last 8 somites.
TS20: tail somite	Present	Regionally restricted	6B	Termination of expression in anterior region of tail.

Structure	Level	Pattern	Image	Note
TS20: somite	Present	Regionally restricted	6C	Expression only in the anterior 38 body segments; no expression in about the last 8 somites.
TS20: tail somite	Present	Regionally restricted	6C	Termination of expression in anterior region of tail.

Structure	Level	Pattern	Image	Note
TS14: trunk somite	Present	Regionally restricted	7A , 7B	Interrupted expression at level of 8th somite.

Structure	Level	Pattern	Image	Note
TS19: trunk somite	Present	Regionally restricted	7C	Interruption of expression for 2 segments in the tail, reappearing for 2 normal and one weakly expressing segment, with no expression in the last 2 somites.

Structure	Level	Pattern	Image	Note
TS19: sclerotome	Present	Regionally restricted	8A	Expression in entire sclerotome, strongest in lateral portion.
TS19: spinal nerve	Absent		8A
TS19: blood vessel	Absent		8A	No expression in intersegmental vessels.

Structure	Level	Pattern	Image	Note
TS19: sclerotome	Present	Regionally restricted	8B	Expression in entire sclerotome, strongest in lateral portion.
TS19: spinal nerve	Absent		8B
TS19: blood vessel	Absent		8B	No expression in intersegmental vessels.

Structure	Level	Pattern	Image	Note
TS19: tail somite	Present	Regionally restricted	8C	No expression in 2 youngest somites.

Structure	Level	Pattern	Image	Note
TS19: tail sclerotome	Present	Regionally restricted	8D	Towards end of tail, sclerotomal expression in the fifth but one somite.

Structure	Level	Pattern	Image	Note
TS19: tail somite	Present	Regionally restricted	8E	Onset of expression in the epithelial second last somite.

Structure	Level	Pattern	Image	Note
TS19: tail somite	Absent		8F	No expression in the newly formed somite.

Structure	Level	Pattern	Image	Note
TS14: somite	Present	Regionally restricted	8G	Expression in the just de-epithelialising somites.

Structure	Level	Pattern	Image	Note
TS13: paraxial mesenchyme	Present	Regionally restricted	8H	Mesodermal expression on both sides of the neuroectoderm.

Structure	Level	Pattern	Image	Note
TS14: embryo	Absent		8I	No expression in the posterior body region.

Structure	Level	Pattern	Image	Note
TS19: embryo	Present	Regionally restricted	8J	Stepwise reduction of expressing zone both dorsolateral and ventromedial to the neural tube.

Structure	Level	Pattern	Image	Note
TS19: embryo	Weak	Regionally restricted	8K	Stepwise reduction of expressing zone both dorsolateral and ventromedial to the neural tube.

Structure	Level	Pattern	Image	Note
TS19: embryo	Absent		8L	Loss of expression towards posterior margin of hindlimbs.

Structure	Level	Pattern	Image	Note
TS19: embryo	Present	Regionally restricted	8M

Structure	Level	Pattern	Image	Note
TS19: embryo	Weak	Regionally restricted	8N

Structure	Level	Pattern	Image	Note
TS19: embryo	Absent		8O	Loss of expression at hindlimb level.

Structure	Level	Pattern	Image	Note
TS19: embryo	Present	Regionally restricted	8P	Expression compressed to small spots halfway between midline and surface ectoderm.

Structure	Level	Pattern	Image	Note
TS19: tail	Weak	Regionally restricted	8Q	Slow reduction of expression in tail.

Structure	Level	Pattern	Image	Note
TS19: tail	Trace		8R	Light expression in tail.

Structure	Level	Pattern	Image	Note
TS19: embryo	Present		8S

Structure	Level	Pattern	Image	Note
TS19: embryo	Absent		8T	Authors report expression pausing; expression vanishes completely.

Structure	Level	Pattern	Image	Note
TS19: embryo	Present		8U	Expression reappears posteriorly.