For genic selection, the dynamics of the selected locus are described by d d t x (t ) = s x (t ) (1 − x (t ) ) 1 + 2 s x (t ).
At the selected locus, allele B has a selective advantage s over the alternative allele b.
The constant production of less fit microsatellite alleles in a population ensures that selection continues to act at the selected locus, thereby eliminating less fit microsatellite alleles along with their linked variants.
For example, if a locus is under strong selection, it is quite possible that the selected locus would exhibit a pattern like that in Fig. 5a, even while non-selected loci would show patterns such as in Fig. 5b.
Its fate is jointly determined by direct selection on locus A, linkage to the selected locus B, migration, and random genetic drift.
Although microsatellite markers are often assumed to be neutral (see [ 14]), they can be affected by selective forces if linkage disequilibrium with a selected locus occurs, an effect known as "hitchhiking" [ 15].
Positive selection results in linkage disequilibrium adjacent to the selected locus, the extent of which can be used to estimate the age of alleles.
Selective sweeps are the signature of a strong selection event where the incremented frequency of a selected locus in a population is accompanied by hitchhiking of the flanking genomic regions [ 34, 35].
Theory suggests that hard and soft selective sweeps can affect patterns of LD around the selected locus and that these can be separated from neutrally evolving regions (Pokalyuk 2012).
Higher levels of recombination allow for the efficient action of selection thereby targeting reductions of genetic polymorphism to the selected locus, whereas low levels of recombination subject neighboring polymorphisms to the effects of background selection or genetic hitchhiking.
Co-evolution in a pathogen-plant interaction is characterized by the development of resistance in the host and virulence in the pathogen, with natural selection affecting the type of genetic polymorphism found at a selected locus.
