ChIP assay - about input - (Nov/07/2012 )

Dear all,
I did chIp assay with 3 gene A, B, C. After Q-PCR, I did electrophoresis for input sample and target gene sample. the bands of all target gene samples are very clear. About input, the band of gene A and C are clear, but there is no band of gene B. I can't explain what happen. Please help me to improve my experiment. Thank you very much.

MAI

I believe the problem could be due to technical issues: accidental loss of DNA, impurities in DNA, etc. Since you already got other samples to work, just repeat it to see if you are luck the next time.