Isolation by distance in liatris cylindracea

Abstract

SEVERAL factors may cause genetic correlation-that is a genetic relationship between individuals within a population-including small population size, self-fertilisation, positive assortative mating or isolation by distance. Isolation by distance occurs when gene dispersal is limited so that distant populations in a series or remote areas within a population become genetically differentiated. Under an isolation-by-distance model of genetic differentiation, spatial distance and genetic correlation between individuals or populations are expected to be negatively related, that is, the greater the distance the smaller the genetic correlation. I wish to present evidence for isolation by distance in the plant, Liatris cylindracea Michx. (Compositae), obtained by a genetic distance analysis of gene frequencies at 27 allozyme loci. This analysis revealed genetic differentiation across very small distances and demonstrated that a restriction of gene flow has a profound effect on the spatial distribution of alleles within a population. © 1974 Nature Publishing Group.