6. Population Size and Evolution Flashcards
Random Genetic Drift Theory
Populations can change gradually over time, even with no selection pressure
Viviparous Lizard
Example of Random Genetic Drift
- Gives birth
- Population in alps - never evolved to give birth
- Population in Spain - Re-evolved to lay eggs
Types of mutation that affect genetic drifting
Neutral & Silent
- Adaptive or deleterious is responding to pressure
Large pool vs Small Pool
Genetic drift acts faster on small pool
Large population
many individual
large gene pool
Small population
small gene pool
larger gene frequency
Minimum viable population
The lowest number of individuals a population can contain before they face extinction
- Size necessary for survival between 100~1000 years
Major models for evolution in small populations
founder effect
Genetic bottleneck
Genetic Diversity of Founding Population
Founding group of a new population has less or different genetic diversity than the source population
Founder Population
Sub-set of the genetics of the original population
Trends Found in Founder Population Change
Genetic Drift
Novel neutral / Silent mutation
Overrepresentation of founder mutation
Founder Mutation
Rare mutation in one of the founding members of a population
- Tend to be in higher genetic frequency than parent population
Retinitis Pigmentosa
Genetic disease in Tristan da Cunha
- 1:4000 individuals worldwide
- ~1:33 in Tristan da Cunha
Leber Heredity Optic Neuropathy
Mitochondrial Genetic Condition
85% of people suffering in QC is from one person in 1669
Genetic Bottleneck
- Population Bottleneck
- Sudden and drastic decline
e. g Golden Hamster(?) - more like founder effect
e. g - Cheetah - Share 99% of alleles
