Why I can see non-specific product and I can't see my exprect PCR product. Half a year ago I prepared PCR and this reaction was working in this time. Last time I prepared PCR and my reaction didn't work. I try optymalize my reaction again. I used many of ways. I check my reagents and a lof of stuff. When I prepared my PCR at the other lab (at other department)this reaction was working (I used the same DNA, reagents, water). After I prepared my PCR in my lab and this reaction didn't work (I used the same DNA, reagents, water). In my reaction is a non-specific product that doesn't interfere with reading result. This product also appeared when my reaction was working and appears now but the expected product is missing.
I'll be grateful for help