ESPL1 and Infertility: Separase+/S1121A/EIIa-Cre mice were also infertile (unpublished data), indicating the infertile phenotype in the mutant mice is caused by the separase point mutation rather than by heterozygosity for Meox2 or an effect of Cre. Because of sexual dimorphism arising from the separase point mutation, the analysis of the female phenotype will be reported elsewhere.