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VARIANCE‐INDUCED PEAK SHIFTS
Author(s) -
Whitlock Michael C.
Publication year - 1995
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/j.1558-5646.1995.tb02237.x
Subject(s) - biology , variance (accounting) , population , selection (genetic algorithm) , statistics , genetic drift , constant (computer programming) , population size , evolutionary biology , genetics , genetic variation , mathematics , demography , accounting , artificial intelligence , sociology , computer science , business , gene , programming language
The increase in phenotypic variance that occurs in some populations as a result of bottlenecks and founder events can cause a dramatic increase in the probability of a peak shift from one adaptive state to another. Periods of small population size allow drift in the amount of phenotypic variance. Increases in phenotypic variance, coupled with a constant individual fitness function with multiple peaks, can cause the mean fitness landscape to change from bimodal to unimodal, thereby allowing the population's mean phenotype to change deterministically by selection. As the amount of phenotypic variance is returned to an equilibrium state, the multiple peaks reemerge, but the population has moved from one stable state to another. These variance‐induced peak shifts allow punctuational evolution from one peak to another at a rate that can be much higher than that predicted by Wright's shifting‐balance process alone.