– <i>Ikbkap^Δ20/Δ20</i> mutant embryos are identical to <i>Ikbkap^3loxP/3loxP</i>embryos.

<p>Total number of embryos recovered at each stage is indicated; number of dead embryos is included in parenthesis.</p>a<p>Mutant homozygous (<i>Ikbkap^3loxP/3loxP</i> or <i>Ikbkap^Δ20/Δ20</i>) or compound heterozygous (<i>Ikbkap^3loxP/Δ20</i>) embryos were recovered at Mendelian ratio at E9.5 and E10.5.</p>b<p>The majority of the embryos recovered were alive and appeared to be one day delayed.</p>c<p>∼75% of the embryos were alive, appeared to be one day delayed and exhibited impaired cephalic development and severe cardiac abnormalities, see results.