TPR Test I (Bio)

[Synapsis]

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Can an investigator determine by gross observation of individuals the frequency of the mutant albino gene in a population?

A) Yes, provided it is known that the population is in Hardy-Weinberg Equilibrium
B) Yes, because the frequency of the albino gene decreases over time.
C) No, because gross observation will not distinguish between heterozygotes and normal homozygotes.
D) No, because the frequency of the recessive allele is low.

Answer was A, and I picked C. The reason I didn't pick A is because we learned that no population can ever really exist in HWE. Perhaps I read this too literally, but when I see "the population is in HWE", I say nope, can't be true. Further, why might C be wrong? TPR doesn't give any explanations for their answers, so I'd really appreciate the help!

 

[doctorswole]

i'm guessing this is a question relating to a passage so it is hard to answer without seeing the passage, but i would say C is wrong because albinism is recessive

 

[oxelhs]

i'm guessing this is a question relating to a passage so it is hard to answer without seeing the passage, but i would say C is wrong because albinism is recessive

That's exactly why OP chose C - you wouldn't be able to tell who is homozygous dominant and heterozygous just from observation.

I'm guessing IF the population can be assumed to be in HWE, then we can solve for frequency of the recessives and subsequently the hetero and homozygous dominants.

 

[doctorswole]

That's exactly why OP chose C - you wouldn't be able to tell who is homozygous dominant and heterozygous just from observation.

I'm guessing IF the population can be assumed to be in HWE, then we can solve for frequency of the recessives and subsequently the hetero and homozygous dominants.

i interpreted the question answer differently- gross observation may not allow us to distinguish between homozygous recessive and heterozygous, but this doesn't make any sense because that would imply that albinism is dominant.

even if we assume that you can't tell between homozygous dominant and heterozygous, it is irrelevant because we can still determine recessive trait frequency based on the homozygous recessives alone. (this is assuming hardy weinberg equilibrium, but again, hard to give a comprehensive answer without seeing the passage)

 

[Synapsis]

That's exactly why OP chose C - you wouldn't be able to tell who is homozygous dominant and heterozygous just from observation.

I'm guessing IF the population can be assumed to be in HWE, then we can solve for frequency of the recessives and subsequently the hetero and homozygous dominants.

Right, since p + q = 1, we should be able to do that. Maybe they were just expecting me to gather that we were assuming HWE. In that case I'd just plead poor wording.

And yep this was a passage question, but I obviously can't post the entire passage. The only relevant information from the passage for this question is "scientists applied the principles of Hardy-Weinberg equilibrium to calculate the allelic frequencies in that population". I guess this statement should've convinced me that HWE was a fair possibility.