Probe:	p103
Probe preparation:	Antisense labelled with S35 RNA
Visualized with:	Autoradiography

Structure	Level	Pattern	Image	Note
TS15: myotome	Strong	Regionally restricted	1A/B	Strong expression in the myotomal part of the first 15-18 (mature rostral) somites, but not in less mature caudal somites.

Structure	Level	Pattern	Image	Note
TS15: myotome	Absent		1D/E	Strong expression in the myotomal part of the first 15-18 (mature rostral) somites, but not in less mature caudal somites.

Structure	Level	Pattern	Image	Note
TS15: trunk myotome	Strong		2A/B
TS15: common atrial chamber cardiac muscle	Present		2A/B	Expression transiently seen in cardiomyocytes over both atrium and ventricle; intensity was significantly weaker than seen in somites.
TS15: primitive ventricle cardiac muscle	Present		2A/B	Expression transiently seen in cardiomyocytes over both atrium and ventricle; intensity was significantly weaker than seen in somites.

Structure	Level	Pattern	Image	Note
TS17: myotome	Strong	Regionally restricted	3A/B	Expressed in the myotomal part of most somites, both rostral and caudal.

Structure	Level	Pattern	Image	Note
TS17: 1st branchial arch mandibular component mesenchyme	Present	Regionally restricted	4B	Expressed only in a small group of cells within the most rostral of the extramyotomal premuscle cell masses, in the dorsolateral part of the first (mandubular) arch.

Structure	Level	Pattern	Image	Note
TS17: 2nd branchial arch mesenchyme	Absent		5C	Expressed only in a small group of cells within the first (mandubular) arch, not in the dorsolateral part of the 2nd visceral arch, hypoglossal cords, and laryngeal muscle anlage.
TS17: head mesenchyme	Absent		5C	Expressed only in a small group of cells within the first (mandubular) arch, not in the dorsolateral part of the 2nd visceral arch, hypoglossal cords, and laryngeal muscle anlage.

Structure	Level	Pattern	Image	Note
TS19: trunk myotome	Present	Single cells	6D	Expressed in the diaphragmal precursor cell masses, where only few positive cells could be found.

Structure	Level	Pattern	Image	Note
TS19: trunk myotome	Strong	Regionally restricted	7C	Strong hybridization in myotomes above the limb buds.
TS19: hindlimb bud mesenchyme	Present	Regionally restricted	7C	In the posterior part of the limb bud, only expressed in a few cells in the dorsal premuscle cell masses.

Structure	Level	Pattern	Image	Note
TS19: trunk myotome	Strong	Regionally restricted	7G	Strong hybridization in myotomes above the limb buds.
TS19: hindlimb bud mesenchyme	Absent		7G	No expression in the dorsal and ventral premuscle cell masses in the anterior regions of the limb bud.

Structure	Level	Pattern	Image	Note
TS20: head mesenchyme	Present	Single cells	8G , 8C	In the most superficial muscle (platysma) anlage in the pharyngeal region, only expressed in few cells.

Structure	Level	Pattern	Image	Note
TS13: embryo	Absent
TS13: heart	Absent

Structure	Level	Pattern	Image	Note
TS14: embryo	Absent
TS14: heart	Absent

Structure	Level	Pattern	Image	Note
TS17: heart	Absent			No signal detected in the heart region at this stage.

Structure	Level	Pattern	Image	Note
TS19: perioptic mesenchyme	Present	Regionally restricted		Expressed in the extraocular muscle rudiments.
TS19: 1st branchial arch	Present			Expressed in muscle-forming regions delineated in previous stages, including parts of the 1st and 2nd branchial arches, hypoglossal cords, and laryngeal muscle anlage.
TS19: 2nd branchial arch mesenchyme	Present			Expressed in muscle-forming regions delineated in previous stages, including parts of the 1st and 2nd branchial arches, hypoglossal cords, and laryngeal muscle anlage.
TS19: head mesenchyme	Present			Expressed in muscle-forming regions delineated in previous stages, including parts of the 1st and 2nd branchial arches, hypoglossal cords, and laryngeal muscle anlage.
TS19: forelimb bud mesenchyme	Present
TS19: heart	Absent			No signal detected in the heart region at this stage.

Structure	Level	Pattern	Image	Note
TS20: forelimb mesenchyme	Present
TS20: head mesenchyme	Present
TS20: hindlimb mesenchyme	Present
TS20: myotome	Present
TS20: heart	Absent			No signal detected in the heart region at this stage.