Table 1. Classification of the Staining Patterns in EPFL2pro::GUS.

Stage*	Frontal**	Non-frontal***		Total examined
		Symmetric	Asymmetric
Globular	3	0	4	7
Heart	16	10	0	26
Torpedo	11	8	0	19

*For the definition of frontal and sagittal longitudinal views at the heart and torpedo stages, see Long and Barton (1998). For the globular stage, embryos with the frontal view are those showing expression only at the apical center. **Number of embryos with frontal longitudinal view, from which the symmetry of the staining cannot be judged. ***Number of embryos with sagittal longitudinal, top, or oblique views, from which the symmetry of the staining can be judged.