Lecture 11:
Chapter 5: Modelling genetic drift with coalescence theory
The coalescent process:
- So far: we have considered drift by looking forward. We considered the probability that two
alleles were identical.
- Another way is to look backwards in time and to consider the time scale.
,
,Assumptions Wright-Fisher population model:
- Population size N is constant through time
- Each individual gets replaced every generation
- Next generation is drawn randomly from a large gamete pool
- Only genetic drift is manipulating the allele frequencies
, The coalescent process:
- Coalescence theory shows how the properties of samples of alleles from populations depend
on the genealogy connecting them.
- Two distinct processes:
o The formation of a genealogy for the alleles in a sample
o The imposition of mutations on the tree.
Chapter 5: Modelling genetic drift with coalescence theory
The coalescent process:
- So far: we have considered drift by looking forward. We considered the probability that two
alleles were identical.
- Another way is to look backwards in time and to consider the time scale.
,
,Assumptions Wright-Fisher population model:
- Population size N is constant through time
- Each individual gets replaced every generation
- Next generation is drawn randomly from a large gamete pool
- Only genetic drift is manipulating the allele frequencies
, The coalescent process:
- Coalescence theory shows how the properties of samples of alleles from populations depend
on the genealogy connecting them.
- Two distinct processes:
o The formation of a genealogy for the alleles in a sample
o The imposition of mutations on the tree.
