Question

Pre-lab questions 1. How can you test a food to find out if it contains material derived from a genetically modified organism (GMO)? 2. In what organelles is plant DNA located? 3. Many foods containing GM crops are highly processed. Can you suggest how DNA from whole plants may differ from that extracted from processed foods, e.g., corn chips cornmeal, etc.? 4. What molecules are present in the cell that might interfere with DNA extraction? 5. Why do you also perform analysis on food that is known to be a non-GMO food control?

Answer 1

1.) The PCR or Polymerase Chain Reaction can be carried out to test whether a food contains materials derived from GMO. Here, DNA is isolated from genetically modified foods and then they are subjected to PCR .This helps in detection of particular sequences of DNA that have been inserted into the GMO as PCR amplifies the DNA sequence.

Elisa test can also be performed in order to detect presence of particular proteins in the food sample.

2.) DNA in plants is found in the nucleus,chloroplast and mitochondria.

3.) DNA extracted from whole plants are mostly intact whereas heat or high temperature or use of certain chemical compounds during food processing can result in the DNA denaturation and lead to its fragmentation.

4.) Enzymes(DNase) and various enzyme cofactors (metal ions) present in cells may interfere with the extraction as they tend to cleave the DNA leading to its degradation.

5.) We always perform analysis on food that is a non-GMO control because it helps us to confirm that the food samples are free of contamination and also helps in the comparison of the non-GMO banding pattern.