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 10-28) 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.Which one of the choices listed below is the best control for clarifying the results of her assay? Explain your answer.
Figure 10-28

Question

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 10-28) 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.Which one of the choices listed below is the best control for clarifying the results of her assay? Explain your answer. 
Figure 10-28

Quizplus · Accepted Answer

A PCR assay using blood from an uninfected person would be the best control as it would allow for comparison of the PCR product obtained from infected patients to a negative control. This would help to confirm that the PCR products obtained from the infected patients are indeed specific to the viral genome and not due to any other factors such as non-specific amplification. Using blood from a newly infected patient who does not yet show symptoms may not be the best control as they may still have low levels of the virus in their blood which could lead to false positives. Using blood from a dog may not be relevant as dogs are unlikely to contract the same virus as humans. Repeating the experiments with a new tube of polymerase may not address the potential issue of a lack of negative control.

Your Friend Works at the Centers for Disease Control and Prevention