Antibody:

anti-MyoD

Structure	Level	Pattern	Image	Note
TS17: forelimb bud mesenchyme	Present	Regionally restricted	3E	Rare co-expression with Cxcr4.

Structure	Level	Pattern	Image	Note
TS19: forelimb bud mesenchyme	Present		3F	Rare co-expression with Cxcr4.

Structure	Level	Pattern	Image	Note
TS18: mesenchyme derived from somites 01-04	Present	Regionally restricted	5A	Expression in muscle progenitors along hypoglossal cord.
TS18: branchial arch mesenchyme derived from head mesoderm	Present	Regionally restricted	5A	Expression in muscle progenitors colonizing mesenchyme of first branchial arch.

Structure	Level	Pattern	Image	Note
TS18: 1st branchial arch mesenchyme derived from head mesoderm	Weak	Regionally restricted	5B	Reduction in number of expressing muscle progenitor cells in first branchial arch.

Structure	Level	Pattern	Image	Note
TS18: 1st branchial arch mesenchyme derived from head mesoderm	Weak	Regionally restricted	5C	Reduction in number of expressing muscle progenitor cells in first branchial arch.

Structure	Level	Pattern	Image	Note
TS18: 1st branchial arch mesenchyme derived from head mesoderm	Absent		5D	Authors report absence of muscle progenitors in first branchial arch.

Structure	Level	Pattern	Image	Note
TS19: branchial arch mesenchyme derived from head mesoderm	Absent			Authors report absence of muscle progenitors in first branchial arch.

Structure	Level	Pattern	Image	Note
TS18: forelimb bud mesenchyme	Present	Regionally restricted	6A	Expression in muscle progenitor cells.

Structure	Level	Pattern	Image	Note
TS18: forelimb bud mesenchyme	Weak	Regionally restricted	6B	Reduction in number of expressing cells compared to control embryos, more pronounced in distal than in proximal domain of dorsal limb.

Structure	Level	Pattern	Image	Note
TS18: forelimb bud mesenchyme	Present	Regionally restricted	6C	Expression in muscle progenitor cells.

Structure	Level	Pattern	Image	Note
TS18: forelimb bud mesenchyme	Weak	Regionally restricted	6D	In dorsal and ventral limb, number of expressing cells further reduced compared to Gab1-/- mutant embryos.

Structure	Level	Pattern	Image	Note
TS21: tongue extrinsic pre-muscle mass	Present		7A
TS21: tongue intrinsic muscle	Present		7A

Structure	Level	Pattern	Image	Note
TS21: tongue extrinsic pre-muscle mass	Present		7B	No major difference within tongue muscle compared to controls.
TS21: tongue intrinsic muscle	Present		7B	No major difference within tongue muscle compared to controls.

Structure	Level	Pattern	Image	Note
TS21: tongue extrinsic pre-muscle mass	Present		7C
TS21: tongue intrinsic muscle	Present		7C

Structure	Level	Pattern	Image	Note
TS21: tongue intrinsic muscle	Present		7D	Only a fragment of intrinsic tongue muscle was present.
TS21: tongue extrinsic pre-muscle mass	Present		7D	Overall size of tongue was very small

Structure	Level	Pattern	Image	Note
TS21: forearm mesenchyme	Present	Regionally restricted	7E	Expression in proximal part of lower forelimb.

Structure	Level	Pattern	Image	Note
TS21: forearm mesenchyme	Present	Regionally restricted	7F	Expression in proximal part of lower forelimb. No reproducible difference between Cxcr4+/- and -/- embryos.

Structure	Level	Pattern	Image	Note
TS21: forearm mesenchyme	Present	Regionally restricted	7G	Expression in proximal part of lower forelimb. Limb muscle was affected.

Structure	Level	Pattern	Image	Note
TS21: forearm mesenchyme	Present	Regionally restricted	7H	Expression in proximal part of lower forelimb. Major differences in limb muscle compared to Gab1-/- mice.