Table 1—source data 1. Deleting the remaining p110α from the trophoblast in Hom-P does not affect fetal viability at day 19 of pregnancy.Frequency of viable fetuses in a litter are displayed, with data from n = 15 litters. Offspring genotypes were determined by conventional PCR, and in the case of Cyp19Cre mutants, additionally by qRT-PCR to identify those with a sufficient level of Pik3ca deletion (frequency is in parentheses). When the cut off for Pik3ca deletion in the placenta using qRT-PCR was applied (<65% for Het-P and <30% for Hom-P), the frequency of Cyp19Cre mutants was ~50% less.