Reporter:	lacZ
Antibody:	anti-B-galactosidase (Cappel/ICN/MP Biomedicals)

Structure	Level	Pattern	Image	Note
TS15: 1st branchial arch	Present		1A
TS15: surface ectoderm	Present	Diffuse	1A

Structure	Level	Pattern	Image	Note
TS17: 1st branchial arch	Present		1B
TS17: 2nd branchial arch	Present		1B
TS17: muscle tissue	Present		1B	Expression was detected in muscle anlagen.

Structure	Level	Pattern	Image	Note
TS19: 1st branchial arch maxillary component	Present	Regionally restricted	1C	A broad domain of expression was detected in the posterior half of the maxillary component.
TS19: 1st branchial arch	Present	Regionally restricted	1C	A smaller more dorsal expression domain was detected between the maxillary and mandibular components.
TS19: 2nd branchial arch	Present		1C

Structure	Level	Pattern	Image	Note
TS20: mandible primordium	Present		1D
TS20: maxillary process	Present		1D
TS20: muscle tissue	Present	Regionally restricted	1D	A fan-shaped anlage originating ventral to the otic vesicle and inserting on the ventral aspect of the mandible seems to be the anlage for a mandibular depressor, which derives from the second branchial arch. One crescent-shaped anlage just anterior to the eye seemed to extend toward the dorsal aspect of the jaw.

Structure	Level	Pattern	Image	Note
TS21: cranial muscle	Present		1E

Structure	Level	Pattern	Image	Note
TS15: 1st branchial arch	Present		1F	No significant anatomical change was observed in the mutant.
TS15: surface ectoderm	Present	Diffuse	1F

Structure	Level	Pattern	Image	Note
TS17: 1st branchial arch	Present	Regionally restricted	1G	The beta-Gal-positive area was largely reduced.
TS17: 2nd branchial arch	Present		1G	No significant change in expression was observed in the second branchial arch.
TS17: muscle tissue	Present		1G	Expression was detected in muscle anlagen.

Structure	Level	Pattern	Image	Note
TS19: 1st branchial arch maxillary component	Present	Regionally restricted	1H	The mutant maxillary component showed ectopic expression that resembled the second arch expression.
TS19: 2nd branchial arch	Present		1H	No significant defect was noted in the mutant second branchial arch expression domain.

Structure	Level	Pattern	Image	Note
TS20: mandible primordium	Weak	Regionally restricted	1I	The components of the jaw were vestigial in mutants, and only a few residual blue spots were observed in these regions.
TS20: maxillary process	Weak	Regionally restricted	1I	The components of the jaw were vestigial in mutants, and only a few residual blue spots were observed in these regions.
TS20: muscle tissue	Present	Regionally restricted	1I	The anlage was present, but was no longer fan-shaped in mutants. The crescent-shaped anlage just anterior to the eye was significantly shorter in mutant.

Structure	Level	Pattern	Image	Note
TS21: cranial muscle	Present	Regionally restricted	1J	Severe deformities of muscle anlagen were noted.