The common Tm without Restriction site is 61 degrees and the Tm with Restriction site is 71 degrees. The reaction conditions i followed is 95 degrees 3 mins, 95 degrees 30 secs, Tm (60-68) degrees (perfomed both gradient (35 cycles) and touch down (8-10 cycles each , extension 72 degrees (1.5 min, size 1500 bp), final extension 72 degrees 5 mins. I have used Mgcl2 as well. All the PCR components work well as actin shows the band in the gel, but target gene does not amplify, primer dimer is visible (i had to select that set of primers to cover desired length). Kindly guide