<i>Rbpj</i>^<i>flox</i><i>;Nkx2</i>.<i>5-Cre</i> embryos show perinatal lethality.

Distribution of the different genetic combinations resulted from the intercross of Rbpj flox/+;Nkx2.5Cre males with Rbpj flox/flox females compared to the expected Mendelian proportions.