Medical genetics: founder effect: practice question

A Anatomy question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Anatomy · Medical genetics: founder effect

Sample item

A rare autosomal recessive disease is unusually common in an isolated village founded by a few families, one of whom carried the allele. What is the mechanism?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

C. Founder effect

In the founder effect, a small group that starts a new population carries only a sample of the parent gene pool, so a rare allele can become common. Isolation and later inbreeding sustain it. Heterozygote advantage would need a benefit to carriers.

Option by option

  • A. Negative assortative mating

    Negative assortative mating means unlike individuals mate, which would not concentrate an allele.

  • B. Mutation-selection balance

    Mutation-selection balance keeps a harmful allele at a low steady frequency.

  • C. Founder effect (correct)

    Correct. A few founders carrying the allele raise its frequency in the isolate.

  • D. Heterozygote advantage

    Heterozygote advantage keeps an allele common because carriers survive better, which the stem does not describe.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

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Questions about this Anatomy question

What is the answer to this Anatomy question?

The best answer is C, Founder effect. In the founder effect, a small group that starts a new population carries only a sample of the parent gene pool, so a rare allele can become common.

Why is "Negative assortative mating" not the answer?

Negative assortative mating means unlike individuals mate, which would not concentrate an allele.

Why is "Mutation-selection balance" not the answer?

Mutation-selection balance keeps a harmful allele at a low steady frequency.

Why is "Heterozygote advantage" not the answer?

Heterozygote advantage keeps an allele common because carriers survive better, which the stem does not describe.

What concept does this question test?

It tests Medical genetics: founder effect in Anatomy. Isolation and later inbreeding sustain it. Heterozygote advantage would need a benefit to carriers.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Medical genetics: founder effect?

Learn every nerve by its route, its muscles and what a lesion looks like at the bedside. That one habit answers a large share of questions. Then use the flashcards and the other Anatomy questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.