Probe:	Irx1 cDNA8
Probe preparation:	Antisense labelled with digoxigenin RNA

Structure	Level	Pattern	Image	Note
TS11: embryo mesoderm	Present			Expression is present in the mesoderm of the head fold.

Structure	Level	Pattern	Image	Note
TS20: interventricular septum	Present		1B Irx1
TS20: forelimb	Present		1B Irx1
TS20: rib pre-cartilage condensation	Present		1B Irx1
TS20: head mesenchyme	Present		1B Irx1
TS20: heart	Present		1B Irx1
TS20: facial ganglion	Present		1B Irx1
TS20: vestibulo-cochlear ganglion	Present		1B Irx1
TS20: metencephalon	Present		1B Irx1
TS20: spinal cord	Present		1B Irx1	Expression is present in the neural tube.
TS20: otic capsule	Present		1B Irx1
TS20: skin	Present		1B Irx1

Structure	Level	Pattern	Image	Note
TS19: metencephalon	Present	Regionally restricted	2A	Expression is found in the ventral region.
TS19: midbrain	Present	Regionally restricted	2A	Expression is found in the ventral region.
TS19: metencephalon basal plate	Strong	Regionally restricted	2A	Expression is found in the sensory region and medial region of the motor part of the pons.
TS19: cerebellum primordium	Strong		2A
TS19: trigeminal ganglion	Strong		2A

Structure	Level	Pattern	Image	Note
TS19: neural tube ventricular layer	Present		2G
TS19: neural tube alar columns	Present		2G	Expression is in the mantle layer.
TS19: neural tube lateral wall	Present		2G	Expression is present in the interneuron region.
TS19: neural tube basal columns	Weak		2G	Expression is in the mantle layer.
TS19: neural tube floor plate	Weak		2G
TS19: notochord	Weak		2G
TS19: rib pre-cartilage condensation	Present		2G
TS19: spinal ganglion	Trace		2G	Expression was not observed in every experiment, indicating low levels of expression.

Structure	Level	Pattern	Image	Note
TS19: inner ear	Present		2M	Expression is present in the otic vesicle.
TS19: acoustic ganglion	Strong		2M
TS19: facial ganglion	Present	Regionally restricted	2M	Expression is present in the ganglia medial to the cranial cardinal vein.
TS19: metencephalon basal plate	Present	Regionally restricted	2M	Expression is present in the pons.

Structure	Level	Pattern	Image	Note
TS21: dermis	Present		3B
TS21: epidermis	Present	Regionally restricted	3B	Expression is seen in the body; virtually none is seen in the head.
TS21: vibrissa follicle	Present		3B	Expression is present in the germinal matrix.

Structure	Level	Pattern	Image	Note
TS21: vibrissa follicle	Weak		3C	Expression is present in the germinal matrix.
TS21: dermis	Present	Regionally restricted	3C	There is no expression at the level of the hair shaft.

Structure	Level	Pattern	Image	Note
TS21: lower jaw molar	Present		3H
TS21: upper jaw molar	Present		3H

Structure	Level	Pattern	Image	Note
TS15: limb	Absent

Structure	Level	Pattern	Image	Note
TS17: limb	Present	Regionally restricted		Expression is present proximally with a broader domain anteriorly.

Structure	Level	Pattern	Image	Note
TS19: footplate mesenchyme	Present	Regionally restricted	4A E11.5	Expression is present in the area where digit cartilage condensation will occur.
TS19: handplate mesenchyme	Present	Regionally restricted	4A E11.5	Expression is present in the area where digit cartilage condensation will occur.

Structure	Level	Pattern	Image	Note
TS20: foot pre-cartilage condensation	Present		4A E12.5
TS20: hand pre-cartilage condensation	Present		4A E12.5

Structure	Level	Pattern	Image	Note
TS21: hindlimb digit pre-cartilage condensation	Present	Regionally restricted	4A E13.5	Expression is present in the joint forming region.
TS21: forelimb interphalangeal joint	Present		4A E13.5

Structure	Level	Pattern	Image	Note
TS22: forelimb interphalangeal joint	Present		4A E14.5
TS22: hindlimb interphalangeal joint	Present		4A E14.5

Structure	Level	Pattern	Image	Note
TS21: forelimb interphalangeal joint	Present		4H

Structure	Level	Pattern	Image	Note
TS19: arytenoid swelling pre-cartilage condensation	Strong		5A	Strong expression in the laryngo-tracheal groove mesenchyme, which will develop into laryngeal cartilages and arytenoids.
TS19: trachea mesenchyme	Strong		5A	Strong expression in the laryngo-tracheal groove mesenchyme, which will develop into laryngeal cartilages and arytenoids.
TS19: trachea epithelium	Absent		5A	No expression in the laryngo-tracheal groove endoderm.

Structure	Level	Pattern	Image	Note
TS15: otocyst	Present	Regionally restricted		Expression is present ventrolaterally.

Structure	Level	Pattern	Image	Note
TS17: lung epithelium	Present
TS17: lung mesenchyme	Absent
TS17: somite	Present

Structure	Level	Pattern	Image	Note
TS19: gonad	Absent
TS19: pancreas primordium	Present

Structure	Level	Pattern	Image	Note
TS21: upper jaw incisor	Present
TS21: thalamus	Present
TS21: skin	Present	Regionally restricted		Although expression is present in most of the skin covering the body, there is almost none in the head.
TS21: neural retinal epithelium	Present	Regionally restricted		Expression is present in the marginal zone.
TS21: lobar bronchus epithelium	Present
TS21: lung epithelium	Present
TS21: lobar bronchus mesenchyme	Absent
TS21: lung mesenchyme	Absent
TS21: mammary gland primordium	Absent			There is virtually no expression in the mammary gland.
TS21: alimentary system epithelium	Absent			There is no expression in the endoderm of the gastro-intestinal tract.
TS21: cap mesenchyme	Present			Expression is present in the blastema.
TS21: gonad	Absent
TS21: laryngeal cartilage	Present			Expression is seen in the laryngeal cartilages. None is seen in the laryngeal endoderm.