Lecture 5 - Migration Flashcards
What does migration allow
Migration allows gene flow
This homogeneises populations
Inbreeding coefficient, f
The probability of identity by descent of two alleles drawn from a population
Fixation index, Fst
Compares the probability of identity by descent of two alleles drawn from a subpopulation compared to drawing two alleles from a total population comprised of multiple sub-pupulations
Observed heterozygosisty, Ho
Proportion of individuals that are heterozygous
Expected Heterozygosity, He
Proportion of individuals that are expected to be heterozygous based on hardy weinberg
Fst
This is the proportionate reduction in heterozygosity of the total combined population
F IT
This is the proportionate reduction in heterozygosity of inbred organisms relative to the total population
What is the most inclusive measure of inbreeding?
F IT
Low Fst
Allele frequencies are similar between populations
High Fst
Allele frequencies different between populations
What genetic markers are used to determine genetic population structure?
Allozymes
Sequence data (mtDNA, autosomal, whole/partial genomes)
Microsatellites
Single nucleotide polymorphisms (SNPs)
Microsatellite characteristics?
Usually neutral
Distributed across the genome
In most organisms
Have conserved flanking regions that primers can be designed to anneal to uniquely for amplification
Very variable due to high mutation rate
Scored as length variants
Co-dominant
Relatively easy to amplify even from small amounts of degraded DNA
How related are human populations?
Generally not very different from each other
Island population structure
A way of looking at gene flow
