Here , we report on the expression pattern of Notch 1 4 , Jagged 1 ( Jag 1 ) , Jag 2 , Delta like 1 ( Dll 1 ) , Dll 3 , Dll 4 , Rbpsuh , Deltex 1 ( Dtx 1 ) and Dtx 2 genes during preimplantation development from unfertilized eggs until late blastocyst stage using a RT PCR strategy . ^^^ We show that Notch 1 , 2 , Jag 1 2 , Dll 3 , Rbpsuh and Dtx 2 transcripts are expressed at all stages . ^^^