Notes genetic drift

genetic drift

1. Notes: Genetic Drift (pg 10)

2. Notes: Genetic Drift (pg 10) Genetic Drift = Change in allele frequencies in a population due to chance events

3. Notes: Genetic Drift (pg 10) Genetic Drift = Change in allele frequencies in a population due to chance events More likely to have a large effect in small populations

4. Notes: Genetic Drift (pg 10) Genetic Drift = Change in allele frequencies in a population due to chance events More likely to have a large effect in small populations Unlike natural selection, which favors beneficial traits, genetic drift is random and can cause an increase in traits that are beneficial, detrimental, or neutral

5. Types of Genetic Drift Founder effect: Changes in gene frequency due to colonization of a new area by a limited number of individuals

6. Types of Genetic Drift Founder effect: Changes in gene frequency due to colonization of a new area by a limited number of individuals Example: British colony on Tristan da Cunha island founded by 15 people. 1 colonist carried an allele for a type of blindness. Today, 2% of individuals on the island are blind, compared to <0.01% in the general population

7. 2. Population bottleneck: Change in gene frequency caused by a drastic reduction in the size of a population, usually due to a natural disaster or hunting

8. 2. Population bottleneck: Change in gene frequency caused by a drastic reduction in the size of a population, usually due to a natural disaster or hunting Example: Cheetahs. 2 Bottlenecks: 10,000 years ago (ice age) and 1800’s (hunting). Now cheetahs are very similar genetically, leading to problems associated with inbreeding

9. Output activity (pg 11) Imagine that a massive earthquake kills all humans on Earth except for President Obama and Vice President Biden and their families (they were safely aboard Air Force One). These people will now repopulate the Earth

10. Output activity (pg 11) Imagine that a massive earthquake kills all humans on Earth except for President Obama and Vice President Biden and their families (they were safely aboard air force one). These people will now repopulate the Earth 1. Are these people a representative sample of human genetic diversity? Explain. 2. List at least 5 genetic traits that would be lost due to this population bottleneck