The demographic parameters estimated using IM are: effective population size of the ancestral population and two daughter populations post-divergence (θA, θ1, θ2), the directional migration rate between divergent populations (m1 and m2; i.e. from population 1 into population 2 and from population 2 into population 1) and the time since divergence (t).
Directional transition rate can give equilibrium states when it has the linear form.
We call f(x) directional transition rate, integrating the effects of M x) and the derivative of V x).
The contribution of this paper is the calculation of the directional marginal rates of a group of variables to another group.
The method estimates posterior probability distributions for both ancestral and actual population sizes, directional migration rates between the two populations, and the time elapsed since population splitting.
These same analyses also provided estimates of the time of these founding events as well as directional migration rates between the resulting daughter populations.
This model focuses on seven demographic parameters: the effective size of the ancestral population (NA), the effective sizes of the two daughter populations (N1 and N2), directional migration rates between the two daughter populations (M1 and M2), the divergence time for the two daughter populations (t), and the proportion of the ancestral population that founded daughter population 1 (S).
A weakness in the above determinations is that they are built on assumptions about an equal and bi-directional replication rate for both chromosomes.
For example, both traditional topology-based and flux-analysis approaches regard TIS as peripheral as it is not highly connected and it is not on any uni-directional or rate limiting reactions.
Noteworthy, triosephosphate isomerase (TIS), which catalyzed inter-conversions between glyceraldehydes-3-phosphate and its isomer dihydroxyacetonephosphate, would be regarded as a peripheral component in the system by traditional topology-based and flux-analysis approaches as it was not on any uni-directional or rate limiting steps.
