Probe:	S8 probe2
Probe preparation:	labelled with S35

Structure	Level	Pattern	Image	Note
TS28: decidua	Strong	Regionally restricted		S8 was consistently expressed at high levels in the outer regions of the decidua.
TS9: embryo	Absent			Hybridization was not detected in embryos prepared at 6.5 days of gestation, which lacked mesoderm.

Structure	Level	Pattern	Image	Note
TS10: amniotic fold mesoderm	Weak	Regionally restricted	1A/B	A weak signal was detected in the mesoderm of the posterior amniotic fold.

Structure	Level	Pattern	Image	Note
TS28: decidua	Strong	Regionally restricted	1C	S8 was consistently expressed at high levels in the outer regions of the decidua. Expression was absent in the remainder of the decidua.
TS10: embryo mesoderm	Absent		1C	Authors note that it is possible that the lack of detectable expression in the embryonic mesoderm reflects only a small difference in actual expression between extraembryonic and embryonic mesoderm.
TS10: extraembryonic mesoderm	Trace		1C	Authors note that it is possible that the lack of detectable expression in the embryonic mesoderm reflects only a small difference in actual expression between extraembryonic and embryonic mesoderm.

Structure	Level	Pattern	Image	Note
TS11: embryo mesoderm	Present		2A/B	Due to the curvature of the cylinder-shaped embryo, the plane of section in Fig. 2E and F grazes the mesodermal layer, which results in a rather diffuse appearance of the expression domain.
TS11: embryo	Present	Regionally restricted	2A/B	Hybridization is absent from a posterior region including the primitive streak.

Structure	Level	Pattern	Image	Note
TS11: allantois mesoderm	Moderate	Regionally restricted	2C/D	The border of expression in extraembryonal mesoderm apparently corresponds with the embryonic/extraembryonic boundary. More laterally, embryonic mesoderm at this boundary does not express S8. Signal is observed at all levels from distal to proximal.
TS11: primitive streak	Present	Graded	2C/D	Along the streak, the strength of hybridization increases gradually towards lateral regions, as reflected by the lower posterior expression levels. The region lacking S8 expression is posteriorly more narrow.

Structure	Level	Pattern	Image	Note
TS11: embryo mesoderm	Present		2E/F	Due to the curvature of the cylinder-shaped embryo, the plane of section in Fig. 2E and F grazes the mesodermal layer, which results in a rather diffuse appearance of the expression domain.
TS11: allantois mesoderm	Present	Regionally restricted	2E/F	The border of expression in extraembryonal mesoderm apparently corresponds with the embryonic/extraembryonic boundary. More laterally, embryonic mesoderm at this boundary does not express S8. Signal is observed at all levels from distal to proximal.

Structure	Level	Pattern	Image	Note
TS11: embryo mesoderm	Present		2G/H	Due to the curvature of the cylinder-shaped embryo, the plane of section in Fig. 2E and F grazes the mesodermal layer, which results in a rather diffuse appearance of the expression domain.

Structure	Level	Pattern	Image	Note
TS11: embryo	Present	Regionally restricted	3A/B	Expression was seen in mesoderm, known to spread anterolaterally. No mesodermal cells were observed anteriorly from the S8 expression domain.
TS11: embryo mesoderm	Present		3A/B	Expression was seen in mesoderm, known to spread anterolaterally. No mesodermal cells were observed anteriorly from the S8 expression domain.

Structure	Level	Pattern	Image	Note
TS11: head mesenchyme	Present		3C/D	Expression was present in head mesenchyme flanking the open neural fold.