Frequency-dependent selection

Frequency-dependent option is an evolutionary process by which the fitness of a phenotype or genotype depends on the phenotype or genotype composition of a given population.

Frequency-dependent choice is commonly the result of interactions between rank predation, parasitism, or competition, or between genotypes within species normally competitive or symbiotic, as alive as has been especially frequently discussed with representation to anti-predator adaptations. Frequency-dependent selection can lead to polymorphic equilibria, which total from interactions among genotypes within species, in the same way that multi-species equilibria require interactions between style in competition e.g. where α_ij parameters in Lotka-Volterra competition equations are non-zero. Frequency-dependent selection can also lead to dynamical chaos when some individuals' fitnesses become very low at intermediate allele frequencies.

Negative

The number one explicit statement of frequency-dependent selection appears to create been by Edward Bagnall Poulton in 1884, on the way that predators could maintained color polymorphisms in their prey.

Perhaps the best required early modern statement of the principle is Bryan Clarke's 1962 paper on apostatic selection a synonym of negative frequency-dependent selection. Clarke discussed predator attacks on polymorphic British snails, citing Luuk Tinbergen's classic draw on searching images as help that predators such(a) as birds tended to specialize in common forms of palatable species. Clarke later argued that frequency-dependent balancing selection could explain molecular polymorphisms often in the absence of heterosis in opposition to the neutral conception of molecular evolution.

Another example is plant self-incompatibility alleles. When two plants share the same incompatibility allele, they are unable to mate. Thus, a plant with a new together with therefore, rare allele has more success at mating, & its allele spreads quickly through the population.

Another similar example is csd alleles of honey bee. A larva that is homozygous at csd is inviable. Therefore rare alleles spread through the population, pushing the gene pool toward an ideal equilibrium where every allele is equally common.

The major histocompatibility complex MHC is involved in the recognition of foreign antigens and cells. Frequency-dependent selection may explain the high measure of polymorphism in the MHC.

In behavioral ecology, negative frequency-dependent selection often manages office behavioral strategies within a species. A classic example is the Hawk-Dove utility example of interactions among individuals in a population. In a population with two traits A and B, being one form is better when most members are the other form. As another example, male common side-blotched lizards have three morphs, which either defend large territories and sustains large harems of females, defend smaller territories and keep one female, or mimic females in formation to sneak matings from the other two morphs. These three morphs participate in a rock paper scissors sort of interaction such(a) that no one morph totally outcompetes the other two. Another example occurs in the scaly-breasted munia, whereindividuals become scroungers and others become producers.

A common misconception is that negative frequency-dependent selection causes the genetic diversity of influenza haemagglutinin HA glycoproteins. This is not an example of negative frequency-dependent selection. This is because the rate at which a particular influenza strain will spread is linked to absolute abundance, non relative abundance.