Question

Consider a new virus that causes a life-threatening disease. Two individuals are exposed to high amounts of virus and only one develops disease. Personalized medicine approaches determine that the individual that was “resistant” to the virus carried a mutation in the gene encoding surface protein X. From this information and your knowledge gained in MIBO3500, what is (are) the reasonable hypothesis(es).

Question 16 options:

	A) The “resistant” individual has a stronger immune system than the other individual
	B) The correlation between surface protein X and disease is accidental
	C) Surface protein X causes the infection
	D) Surface protein X is the receptor for the virus
	E) A or D

Answer 1

Answer: Option( D) - Surface protein X is the receptor for the virus.

Explanation : As the question said the individual who was resistant to the virus, carried a mutation in the gene encoding surface protein X, it may be hypothesised that the virus entry to the cell is mediated by this surface protein X. Also the surface protein X may be the receptor for the virus.

The individual who had no mutation for that gene, allowed virus entry so got the infection.

Option (A) is not right as in this scenario the person who had the mutation in the gene encoding surface protein X was resistant to the virus even after being exposed to a high amount of virus. The other individual got the disease. We can't hypothesise about the resistant individual's immune system being stronger than the non - resistant individual based on these data as the resistance is shown to be mediated by a mutation but not by the immune system.

Option (B) is not right because personalised medicine approach has indicated a more or less definite correlation between the surface protein X and the disease occurance. It is to be noted that the individual who had the mutation in the gene coding for protein X was resistant and the other individual without the mutation was sensitive to the virus. Therefore it can not be hypothesised that the relationship between protein X and the disease is accidental.

Option (C) is not the right answer as the cause of the infection is virus not the surface protein X. The individual who had normal (without mutation) surface protein X got the disease after being exposed to high amount of virus. So, it is clear that protein X doesn't cause the disease. It may serve as a receptor for the virus to enter into the cell( by observing the case with both individuals).

Option (E) is not the right option as Option (D) may be the reasonable hypothesis but the hypothesis in option (A) is not right.