- If you were to test the organic or Non-GMO verified food and find GMO DNA present, what would you conclude?
- Does a lack of a band completely exclude the possibility of GMO products? Why or why not?
- Does the presence of a band confirm that GMO products are being used? Why or why not?
23451, 000 bp|11700 bp500 bp200 bp100 bpFig . 1 . Detecting GM foods by PCR. Genomic DNA is extracted from test foods ( Lesson 1 ) and then two PCRreactions are performed on each test food genomic DNA sample ( Lesson 2 ) . One PCR reaction uses primersspecific to a common plant gene ( plant primers ) to verify that viable DNA was successfully extracted from thefood . No matter whether the food is GM or not , this PCR reaction should always amplify DNA ( See lanes 1 and 3of the gel above ) . The other PCR reaction uses primers specific to sequences commonly found in GM crops( GMO primers ) . This PCR reaction will only amplify DNA if the test food is GM ( See lane 4 ) . If the test food isnon – GM , then the GMO primers will not be complementary to any sequence within the test food genomic DNAand will not anneal , so no DNA will be amplified ( see lane 2 ) . To find out whether DNA has been amplified or not ,the PCR products are electrophoresis on a gel and stained to visualize DNA as bands ( Lesson 3 ) . A molecularweight ruler ( lane 5 ) is electrophoresis with the samples to allow the sizes of the DNA bands to be determined .