I am using a 50bp DNA ladder. I have amplified p53 which was supposed to show at 166bp but is apparently at 500bp according to the image. I think the ladder is the problem, why is it starting so far from the well? This is a 2% agarose gel with 2ul EtBr. Voltage was 120 for 1 hour. I used 3ul of the ladder and 2ul dye. What am I doing wrong?
I would double check the band sizes for your brand of DNA ladder. Also looks more like 300bp to me.
Potential causes are your gel is not homogenous which can be resolved by heating for longer in the microwave and mixing more thoroughly. Alternatively the electrodes in your gel tank are faulty so the current on one side of the gel is stronger. Another possibility is some contaminant in your samples is being amplified and not your p53. Are you using primers that are known to work?
Have you tried loading your ladder in the middle of the gel? If the problem persists consider having your PCR product sequenced.
Your ladder seems tilted right side, So one thing is you should load the sample and ladder at the earliest (If you delay, the sample may diffuse laterally as well).
secondly, prefer to run the gel within a range of 70-90 V.
For a better resolution of the DNA and marker i suggest using 3,5 PERCENT Agarose gel.