We examined the expression of 16 candidate genes ( IDH , YEAF Cathepsin B , RAD 50 , TCP 1 NCOR1 , HUEL , STK 6 , ZNF 403 , AOP 2 , EEF1A1 , Hsp 90 , Hsp 40 , AKR1B1 , PGRMC 1 , and DMRT 2 ) in early and late cleaving embryos , by real time PCR . ^^^