Labour seats have, on average, 6,000 fewer electors than Tory ones because of the long-term drift of population from the cities to the shire counties and the leafy suburbs.
Labour constituencies have on average 6,000 fewer electors than Tory ones because of the long-term drift of population from the cities to the suburbs and the shire counties.
This asymmetry leads to a "drift" of population activity, and thus perceived position, over time toward the fovea.
Aside from climatic changes that have caused the gradual drift of populations (for example the desertification of the Middle East, and the formation of land bridges during glacial periods), extreme weather events have caused smaller scale population movements and intruded directly in historical events.
Isolated from natural trees and long period of cultivation seem to be the major causes of the lowest genetic diversity and the highest drift values of population DLP among the planted populations (Table 1, Figure 5 and Additional file 2).
As this is materially impossible in finite populations, this delocalization should be interpreted as the drift of the population over the sequence space [ 8].
This model contrasts sharply with conventional population genetic models in which the existence of a large number of neutral mutations would lead to genetic drift of the population and the individual is the unit of selection rather than a cloud of related variants [ 11].
Scaling F by r reduces the amount of drift of current populations from the ancestral population; thus, structure is difficult to resolve when r is close to 0, while structure is easy to resolve when r is close to 1.
This may not be a surprise given that it should take multiple generations of random genetic drift for population size reductions to be reflected in genetic diversity estimates [47], especially in large populations.
It reflects the very ancient settlement of the region; the subsequent isolation and drift of many inland populations; some subsequent internal population expansions; the introduction of two haplogroups and populations in the mid Holocene, combined with some intermixture among many groups, especially those living along the shorelines.
The persistence of the central geographic barrier is fundamental for ring diversification because it restricts movement of individuals to the ring distribution, thus promoting non-adaptive divergence through the initial colonization of available habitat, genetic drift of each local population, and limiting gene flow among continuous populations around the ring.
