Question

One of the reasons in the given below options is responsible for improper resolve of DNA fragments in the gel —
1) Size of the fragments
2) Negative charge of the DNA
3) Microbial contamination
4) Air bubbles in the gel

Explain the chosen answer.

Answer 1

Explanation:

There are several reason for your problem, as you said those bands were far from your target band those might be primer dimer. but if that is primer dimer the band should be smaller than your target band. you can overcome this problem by hot start.

or your primer is not specific to your target region if that is the case, you can try touchdown PCR that helps to specific binding.

Be careful with contamination because different organism have same sequences with only few nucleotide changes, if you contaminate you get more than one band.