Summary: | We used 16 populations of an alpine tundra grasshopper, Aeropedellus clavatus , to describe patterns of genetic variation within and among isolated populations on the mountain ranges of Colorado. We analyzed the grasshoppers for variation at 25 electrophoretic loci and for chromosomal and morphological variability. We found large amounts of variation within populations, indicating that there has not been a significant long-term reduction in the number of individuals. Estimates of gene diversity (G ST ) indicated that 92% of the total genetic variation is found within populations. These analys es suggest that populations that are now isolated were more continuous during glacial episodes of the Pleistocene. Heterogeneous patchy environments, large population sizes, and overlapping generations have contributed to the maintenance of high levels of genetic variability in the presumed absence of migration and gene flow.
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