Imagine that a Toll-like receptor (TLR) gene has duplicated and mutated, creating a leucine-rich region binding pocket that can now bind to the hemagglutinin protein in the envelope of influenza virus. What do you predict will happen to this novel gene?

Question

A.  It will be selected for and over evolutionary time will become an even better receptor for HA protein.
B.  It will spread from species to species.
C.  It will undergo VDJ rearrangement.
D.  It will continue to mutate, perhaps changing to bind other proteins or becoming deleted.

Clarify Question
What is the key concept addressed by the question?
What type of thinking is required?
 
Gather Content
What do you already know about TLRs? What other information is related to the question?

Choose Answer
Given what you now know, what information is most likely to produce the correct answer?
 
Reflect on Process
Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
 

Answer 1

D.  It will continue to mutate, perhaps changing to bind other proteins or becoming deleted.

Clarify Question
What is the key concept addressed by the question?
        · This question is asking about the fate of a Toll-like receptor gene that has mutated.
What type of thinking is required?
        · Analyze level:
            o This is an analyze question because you have to break TLRs and mutations that occur in them into their component pieces to understand how they function.
 
Gather Content
What do you already know about TLRs? What other information is related to the question?
        · 11 TLRs have been identified in humans.
        · Human TLRs bind to specific antigen types that are components of pathogens.
        · Leucine-rich pockets on TLRs allow greater flexibility for binding with pathogens.
        · Activation of TLRs stimulates innate and adaptive immune responses.
        · Viruses can evade this response by mutating quickly.
        · The influenza virus is notorious for the rapid mutation rate of its HA and NA envelope proteins, which usually makes them poor targets for TLRs.

Choose Answer
Given what you now know, what information is most likely to produce the correct answer?
        · A mutation within a human species for a TLR would not be spread to another species.
        · With this mutation, TLRs are able to recognize specific components of the influenza virus.
        · This recognition would lead to a much faster immune response if the influenza virus is present.
 
Reflect on Process
Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
        · Analyze level:
            o Answering this question correctly depended not only on distinguishing between normal and mutated TLRs, but on your ability to break down, or analyze, the effects of mutation. If you got an incorrect answer, did you remember that TLRs are not usually effective against influenza, or that the leucine-rich pockets that are described would make TLRs much more responsive to influenza? Did you have trouble breaking down the nature of TLRs to determine the correct answer?