Probe:	Hoxa3 probe12
Probe preparation:	Antisense labelled with digoxigenin RNA
Visualized with:	Alkaline phosphatase

Structure	Level	Pattern	Image	Note
TS10: embryo mesoderm	Present		S1M	Transcription initiates earlier than Hoxa1 and Hoxa3.

Structure	Level	Pattern	Image	Note
TS11: embryo mesoderm	Present	Regionally restricted	S1N	Authors report expansion of expression in anterior lateral mesoderm.

Structure	Level	Pattern	Image	Note
TS13: embryo mesoderm	Present	Regionally restricted	S1O	Authors report expansion of expression in anterior lateral mesoderm.

Structure	Level	Pattern	Image	Note
TS12: embryo mesoderm	Present	Regionally restricted	1G

Structure	Level	Pattern	Image	Note
TS13: secondary heart field	Absent		2E	No expression in anterior domain of second heart field (AHF).
TS13: splanchnopleure	Present	Regionally restricted	2E	Expression in splanchnic mesoderm posterior to heart tube.

Structure	Level	Pattern	Image	Note
TS13: secondary heart field	Absent		2E1	No expression in anterior domain of second heart field (AHF).

Structure	Level	Pattern	Image	Note
TS13: endocardial tube	Absent		2E2	No expression in heart tube.

Structure	Level	Pattern	Image	Note
TS13: splanchnopleure	Present	Regionally restricted	2E3	Expression in splanchnic mesoderm located posterior to heart tube.

Structure	Level	Pattern	Image	Note
TS13: splanchnopleure	Present		S6G

Structure	Level	Pattern	Image	Note
TS13: splanchnopleure	Present		S6G inset

Structure	Level	Pattern	Image	Note
TS13: splanchnopleure	Weak	Regionally restricted	S6H	Expression downregulated in splanchnic mesoderm in mutant embryos. Authors report posterior shifting of anterior border of expression in mutant.