The size of DNA fragments can be determined by comparing their migration distance to a standard ladder of known fragment sizes. The smaller fragments will migrate further while larger fragments will remain closer to the well.
A control sample is used as a reference to compare the results of the experimental samples. It ensures that any observed differences in band size or intensity are not due to errors in the electrophoresis process.
The intensity of bands on an electrophoresis gel can indicate the relative amount of DNA present in a sample. The darker and thicker the band, the more DNA is present in that particular fragment.
Some common sources of error in electrophoresis results include incorrect sample loading, insufficient or excessive voltage, contamination of reagents or equipment, and improper gel preparation or handling.
To improve the resolution of DNA bands, one can use a higher percentage gel or adjust the voltage and run time. Additionally, using a DNA stain that specifically binds to DNA can enhance the visibility of bands on the gel.