Which of the following is a factor that does not promote widespread changes in allele or genotype frequencies?

Question

Which of the following is a factor that does not promote widespread changes in allele or genotype frequencies?

BlackTom AI · Accepted Answer

New mutations arise at very low rates per gene per generation (typically 10^-9 to 10^-5), so a single new mutation initially has an extremely small frequency and by itself rarely shifts population allele frequencies broadly.

1) Relevant concepts
- Mutation: the ultimate source of new alleles; per‑locus mutation rates are very small. The expected per‑generation change in allele frequency from mutation alone is roughly Δp ≈ μ(1 − p) − νp (with μ, ν mutation rates), which is tiny when μ is small.
- Natural selection: differences in fitness change allele frequencies by Δp ≈ s p(1 − p) (s = selection coefficient), which can be large if s is appreciable.
- Genetic drift: random sampling causes allele‑frequency variance Var(Δp) ≈ p(1 − p)/(2N); in small populations this can lead to large, rapid changes including fixation or loss.
- Migration (gene flow): with migration rate m, allele frequency change is Δp ≈ m(pmigrant − p), which can substantially alter frequencies if m or the allele frequency difference is large.

2) Step‑by‑step reasoning
- A single new mutation appears in one chromosome in a diploid population of N individuals at initial frequency 1/(2N). Example: N = 1,000 gives initial p = 1/2,000 = 0.0005.
- With a typical mutation rate μ ~ 10^-5, the per‑generation input of new mutant alleles is extremely small compared with the allele pool, so Δp due solely to mutation ≈ μ is on the order of 10^-5 per generation — negligible for rapid, widespread change.
- By contrast, if s = 0.1 and p = 0.1, selection yields Δp ≈ 0.1 × 0.1 × 0.9 = 0.009 per generation (much larger). For drift in a small population (N = 50), Var ≈ p(1 − p)/(100) can produce large stochastic changes. With migration m = 0.1 and a migrant allele frequency difference of 0.5, Δp = 0.05 — again substantial.

3) Why the correct answer is correct
Because mutation rates are very low, mutation alone does not typically produce widespread, rapid shifts in allele or genotype frequencies; it introduces new variation slowly. Widespread changes are more immediately driven by selection, drift (especially in small populations), or migration/gene flow.

4) Why the other options are incorrect
- Natural selection: directly alters allele frequencies according to fitness differences — promotes widespread change.
- Genetic drift: random sampling can cause large frequency shifts or fixation, especially in small populations.
- Migration: gene flow can rapidly change allele frequencies by introducing or homogenizing alleles between populations.

Conclusion: New mutation is the factor that does not promote widespread changes in allele or genotype frequencies, which matches the provided answer "New mutation."

Which of the following is a factor that does not promote widespread changes in allele or genotype frequencies?Single choice

Similar Questions

Which of the following is a factor that, by itself, is least likely to promote widespread changes in allele or genotype frequencies in a large population?

A population geneticist is studying a population of pea aphids and wants to determine whether the proportion p of aphids that are resistant to a particular insecticide is less than 0.40, the proportion reported in a previous study. Which pair of hypotheses is appropriate for this test?

In natural populations, most genes are

The Greater prairie chicken population in Illinois is a living example of which of these ?

A population that is infinitely large and in which mating is completely random is mostly likely to:

Question at position 21 What is the most important determinant of genetic differences between populations of humans across the world?RaceEthnicityGeographic distanceLocal adaptationClear my selection

Question at position 14 Genetic diversity amongst human populations is best explained by __________.cultural differencespopulation sizeethnicityracial categorizesgeographic distanceClear my selection

More Practical Tools for Students Powered by AI Study Helper

Homework AI Solver

Stylized AI Paper Writer

Plagiarism Checker Assistant

Citation AI Academic Writing Tool

In-Class Translation Assistant

AI Note Generator

AI Quiz Answers

Past Exam Questions from University Test Bank

Smart Practice Assistant

Adaptive Practice

Making Your Study Simpler