absolute fitness
Kim Y & Gulisija D 2010 Signatures of recent directional selection under different models of population expansion during colonization of new selective environments. Genetics 184:571-585.
- the Wright-Fisher model, or other models of reproduction that require specifying the population size at a given time, is not convenient to be applied here
- the growth of the derived population must be modeled separately
- the growth rate of the population depends on the exact genetic composition of the population
- the evolutionary dynamics of different alleles is specified by the absolute, rather than relative, fitness
- let WX be the absolute fitness
- the number of offspring in the next generation from each individual is Poisson distributed with parameter WX
- N1 is the current size of pop1
- K1 is the carrying capacity of pop1
- at equilibrium, N1 will fluctuate around K1
- with a large value of N1, the reproduction in this population should approach that of the Wright-Fisher model
- the binomial distribution of offspring number in the latter model converges to a Poisson distribution
- our model of reproduction is similar to the Wright-Fisher model with respect to the offspring distribution
- we may apply the methods of coalescent approximation that were used in other studies under the Wright-Fisher model
- the change in size of the derived population depends on its genetic composition
- the Wright-Fisher model is not adequate
- we therefore constructed a model in which each allele leaves descendants according to its absolute fitness
