Question

8. (10 points) Your friend works at the Centers for Disease Control and Prevention and has discovered a brand-new virus that has recently been introduced into the human population. She has just developed a new assay that allows her to detect the virus by using PCR products made from the blood of infected patients. The assay uses primers in the PCR assay that hybridize to sequences in the viral genome. Your friend is distraught because of the result she obtained (see figure below) when she looked at PCR products made using the blood of three patients suffering from the viral disease, using her own blood, and using a leaf from her petunia plant. You advise your friend not to panic, as you believe she is missing an important control. What control is she missing? Explain your answer. patient 1 patient 2 patient 3 Self petunia E

Answer 1

An important control is missing which is healthy control. She needs to check if the primers she identified for virus possibly non-specifically amplifying human DNA. For example, the two bands which are common between her and patient samples may be amplified from human DNA, where as the third band missing in her sample and present in patient samples is from virus DNA