Table 1.

Shp2 mutant cell contribution to E10.5 chimeric embryos

Category	Contribution, %	No. examined	wt Phenotype, %	Mutant phenotype (no.)
Low	5–25	20	100	—
Medium	25–50	15	93	Spina bifida (1)
High	50–75	22	5	Spina bifida (13) Second neural tube (8)