BIOL 290 Lecture Notes - Lecture 7: Genetic Drift, Allele Frequency, Allele
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Non-selective causes of Evolution
Thursday, October 4, 2018
4:01 PM
• Founder Effect
• Interbreeding
• Mutations
• Genetic Drift
o Genetic drift, founder effect, and interbreeding
most important in small populations
1. Founder Effect:
• Individuals who leave a larger population and move to
a new habitat; founders of the new population that
will grow
• Allele frequencies in the new population are most
likely due to sampling
o Bottleneck effect: reducing a population to a few
members; can eliminate genetic diversity
• Ex: Northern elephant seals; 20 remained; (40
alleles) now 175,000 vs Southern elephant seals
who did not face an extinction crisis; have much
more diversity in their population
• French Canadians: 8,500 French Settlers
colonized the province between 1608-1759
o Consequences: