EvolutionLesson 2 of 2 in the course Genetic drift and gene flow

Founder Effects: Drift, Inbreeding, Migration, and Population History

5 flashcards · 5 quiz questions · 5 match pairs · 5 fill-in sentences · English

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Summary

This lesson introduces the founder effect, explains how a small founding group can differ genetically from its source population, and shows why random sampling matters.

The founder effect is the loss or change of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population. The founders carry only some of the alleles—the different forms of genes—present in the original population.

All flashcards

Founder effect
Genetic change or loss of variation when a new population begins with a small, potentially unrepresentative sample from a larger population.
Genetic drift
Change in allele frequencies due to chance rather than necessarily due to natural selection.
Fixation
The state in which an allele reaches frequency 1 at a gene location in a population.
Founder mutation
A DNA change carried by one or more individuals who help establish a population and inherited by their descendants.
Serial founder effect
Repeated founding of new populations by subsets of preceding populations during geographic expansion.

Quiz questions

  1. In a population, what does it mean for an allele to reach fixation at a gene location?Answer: The allele has frequency 1 at that location.
  2. How can inbreeding affect individuals in a small population?Answer: It can increase homozygosity, making recessive alleles more likely to be expressed.
  3. How can recombination help researchers estimate the age of a founder mutation?Answer: Older mutations tend to have shorter shared DNA segments around them.
  4. What is the relationship between a founder effect and speciation?Answer: A founder effect may contribute to divergence but does not automatically produce a new species.
  5. Which process describes successive migrating groups founding populations from subsets of earlier groups?Answer: A serial founder effect.

Based on the Wikipedia article Founder effect, licensed CC BY-SA 4.0. Adapted into a summary, flashcards and quizzes.

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