Table 3.

Effect of Six2.1 and Bmp4 morpholino injections on dorsal/ventral polarity

Morpholino Injected	Concentration (ng)	Phenotypea,b				n
		Wild-type (class I) (%)	Class II (%)	Class III (%)	Class IV (%)
Uninjected	NA	100	0	0	0	172
Six2.1 (ATG)c	1	89	11	0	0	113
	3	12	75	4	9	92
	6	0	30	65	4	46
Southpaw (ATG)d	1	100	0	0	0	23

		Wild-type	Class I-III	Class IV/V
Uninjected	NA	100	0	0	—	157
Bmp4 (ATG)c	1	99	0	1	—	69
	3	20	56	25	—	126
	6	0	77	23	—	26
Southpaw (ATG)	1	100	0	0	—	23

^aDorsalized phenotypes resulting from Bmp4 MO injection were scored according to reference ⁵² as follows: class I-III, embryos at 24 hpf that lacked tail structures (class I and II) or had shortened twisted tails missing ventral structures (class III); class IV-V, embryos with a reduction of ventral cell types and expansion of notochord and anterior somites at 24 hpf (class IV) and bursting of embryos prior to 24 hpf due to somite expansion and constriction (class V).

^bVentralized phenotypes resulting from Six2.1 MO injection were scored according to reference ⁵³ as follows: class I, wild-type; class II, reduced head, expanded hematopoietic mesoderm; class III, loss of head and notochord; class IV, spindle-shaped embryo with no obvious dorsal/ventral polarity.

^cTwo different morpholinos for six2.1 and bmp4 were injected. Because phenotypes were equivalent for both morpholinos, the data are combined.

^dThe southpaw morpholino gives completely penetrant phenotypes in the lateral plate mesoderm at 250 pg. Concentrations ranging from 250 pg to 2 ng have never produced dorsalized or ventralized phenotypes (this table and RDB data not shown).

NA, not applicable.