Mary performs a PCR reaction and runs it on an agarose gel, using 100-bp ladder
ID: 186736 • Letter: M
Question
Mary performs a PCR reaction and runs it on an agarose gel, using 100-bp ladder as her molecular weight standard. She images the gel using UV light and sees NO bands (no band in her PCR reaction and no bands for her ladder). Which of the following could explain these results? Explain each answer.
1. Mary forgot to add Gel Red when pouring the gel.
2. Mary's PCR product had an unusually high % of G and C bases.
3. Mary connected the electrodes to her gel incorrectly, swapping the positive and negative poles.
Explanation / Answer
1)she forgot to add gel red while pouring
That's the reason why even ladder wasn't stained.
Not (2) because in this case the PCR product would not be seen but atleast the ladder should have been visible as it would have a normal GC content.
Not (3) because in this case she should have realised this mistake as the loading dye(blue) would diffuse out and the dye front would not be visible in the gel.