Flashcards in Drift/Mutation/Flow Deck (24):
The Modern Synthesis
Combined darwins and mendels genetics to see evolution at population level as an explanation of the macro world changes in a micro fashion
Muetral Theory of Evolution
Most of the genome is evolutionarialy nuetral (if it doesn;t effect reproduction it is not selected on)
change in allele frequency over time
What are the deterministic forces of evolution (2)?
natural selection and gene flow
What are the random forces of evolution (2)?
Mutation and Genetic Drift
A change in allele frequency due to random sampling of the population
What is effect of drift like on small populations?
What is the result of genetic drift?
Loss in diversity because alleles become fixed
How can you estimate the effective population size using drift and mutation rate?
Mutations enter the population at a rate u •Most new mutations are lost, some drift to fixation •Larger Ne = slower drift = more genetic variation (m) in the population at any given time -> If you know u and m, you can calculate Ne
•Ne for the ancestral human population is estimated at 4,600-11,200 people (i.e. reproducing adults)!
Migration resulting in the moving of alleles to a new population
What is the result of gene flow?
homogenizes allele frequencies among populations
How is gene flow determined?
Based on the number of people migrating to new populations
Wrights Fixation Index
Genetic variation among populations/
Genetic variation within populations
What does Fst=1 mean?
All the variation is between populations and NONE is within
What does large structure in population mean?
This means that the there is less variation within a population
Founder Effect results in:
less variation in population the farther away populations move from original source
Founder Events+Gene Flow
Create isolation by distance
Error in DNA synthesis leading to new variation
All new genetic variation comes from:
What is mutation influenced by?
Nothing! It is completely random
How can we calculate the number of mutations in population?
Ne times mutation rate times number of generations
a set of variants that are inherited as part of the same stretch of DNA
Why do we look at haplotypes in Y chromosome?
Because there is no recombination (highly conserved)