A pocket of variability in Pinus rigida

Abstract

Steady state gene frequencies around a pocket of differential fitness have been formulated by Hanson (1966) in a generalization of the work of Haldane (1948). A pocket of differential fitness would result in a pocket-of-variability, assuming that the radius of the area of contrasting fitness was large in relation to the vagility of the organism. Conversely, the absence of a pocket-of-variability is predicted whenever dispersal is broad relative to the size of the pocket of differential fitness. Around the pocket, a cline would be established through the interaction of migration and selection. The slope of the cline would depend on the width of the band of intermediate fitness, being steepest where the band was absent. The change in gene frequency with distance from the pocket would be rapid in the band of intermediate fitness values and approach limiting values asymptotically in the areas of contrasting fitness.

Citation

Ledig, F. Thomas; Fryer, John H. 1971. A pocket of variability in Pinus rigida. Evolution 26:259-266