Hello Phyo,

To provide a more accurate answer, I would need additional information regarding your experiment, such as the type of sample, the extraction method, the quantity of RNA deposited, the gel concentration, etc.

However, I'll describe some possible causes in hopes that one of these suggestions will be helpful. Several factors can cause smeary RNA bands on a gel. Here are some potential reasons:

• Loading too much RNA material: Typically, you should load between 0.5-1 µg of RNA (0.5 µg is a good starting point).
• Insufficient migration time: Try running the gel for a longer period to achieve better separation.
• High agarose concentration: Usually, 1% agarose is sufficient for good separation.
• Not denaturing the RNA before loading: Try denaturing the RNA for 2-10 minutes at 70°C, then place it on ice before loading.
• Degraded RNA: Degraded RNA can lead to smeary bands.
• Inappropriate loading dye: Sometimes, the loading dye can affect the sharpness of the bands. Ensure you are using a dye compatible with RNA.
• Intercalating dye issues: Sometimes, the intercalating dye used is incompatible with RNA. Verify that the dye you are using is appropriate for RNA visualization.

Try loading an RNA sample that has been previously verified for its integrity as a positive control. This will help distinguish if the problem is due to issues with your samples or the gel migration experiment.

Feel free to recommend my answer if you find it helpful.

Best regards,

YS

Bands with that low of a molecular weight & that smeared makes degradation the most likely explanation.

Talk to someone in the lab that gets quality RNA & they can help train you.