Hello,
I'm doing PCR and gel electrophoresis on tetranucleotide microsatellite marker. Recently, I have often encountered strange, asymmetrical smears on the gel (images attached). I suspect this is the problem with the gel, since similar smear can be seen on the ladder. Anybody know what could potentially cause this and how do I fix it?
Thank you,
Minh
At what voltage are you running the gel? Too much power could cause high amounts of heat to be generated that could cause distortions. It may also help if you change the buffer (if it the same buffer has been used multiple times) and run in freshly-prepared one. Hope this helps!
Dear Le
This smearing is usually the result of poorly prepared gels, loading undiluted samples into the wells or poor quality samples.
Please also look at the links below. Hope to help you solve your problem.
https://www.researchgate.net/post/What_causes_smearing_in_electrophoresis_with_genomic_DNA
https://www.researchgate.net/post/Smearing_in_agarose_gel_of_PCR_product2
Hello Seied Mehdi Miri
Can you please specify what you mean by "undiluted samples"?
Minh
Hello
Before loading samples into the wells, those samples must be dilute enough to run through the gel without overflowing the wells. If a loaded sample is too concentrated or used an improper dilution factor, the fragments will be too large for the wells and produce smearing.
Thank you for your response Seied Mehdi Miri
I have never diluted my PCR product before and the gel came out justfine some other times. Are you suggesting that I should dilute the product?
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