Picture 1. The 2nd PCR products
1. Negative control
2. Plasmid 4
3. Plasmid 5
4. Plasmid 6
Picture 2. The 2nd PCR products
1. Negative control
2. Plasmid 4
3. Plasmid 5
4. Plasmid 6
I did 2 experiments with the same protocol and primer pairs, but a little different templates. Just look at 2 pictures from the lane 1 to lane 4, they have the same templates. Both of these pictures are the 2nd round PCR results.
My teacher said the picture 2 has correct bands, and the picture 1 has contamination in the lane 2. The difference between 2 experiments is that I used TE1 for the 1st experiment and TE2 for the 2nd experiment to dilute templates. Looking at two pictures, we can say that my TE1 has contamination. But what I am still wondering is that if my TE1 got contamination, why doesn't lane 3 have the same 1kb band like in the lane 2?
I don't know what my templates are which mean if they are real plasmid or just water because my teacher gave me this excercise for me to practice PCR skills.
Hi Trang,
both pictures are named second PCR. Can you update them?
I'm not seeing any contamination of lane 1 in your first PCR. There is a bright primer dimer band. You have different size products from your plasmids in lanes 7 & 8. That means that those plasmids are different from the rest. What size products where you expecting?
Hello Katie,
Thank you for your reply. I am sorry that I didn't explain clear my idea. I have just updated my question. Could you mind reading it one more? Thank you beforehand!
From the updated question I argue that the primer pair is the same in all samples, also TE (1 or 2) is present in all samples, so the only difference is the template. If that is the case you don't have a a TE contamination but rater you made a cross contamination of samples 2 and 4.
Thank you for your answer, Alberto. I would like your idea, but my teacher has checked TE1 with the same protocol, and it is in the lane 6 of the picture below.
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