GENETIC VARIATION IN ALETES ACAULIS AND ITS RELATIVE,THE NARROW ENDEMIC A. HUMILIS (APIACEAE)

We compared the organization of genetic variability in Aletes humilis, a species restricted to seven populations in north-central Colorado, with A. acaulis, a closely related widespread species. Genetic variability was scored at 11 electrophoretically detectable protein loci. Nine of these loci were polymorphic (i.e., P > 0.95) in both taxa, and were used for interpopulation and interspecific comparisons. Levels of genetic variability and patterns of organization of this variability are very comparable in both species. In contrast to many other narrow endemics, A. humilis is not genetically depauperate when compared to its presumed progenitor. Both biochemical and morphological evidence suggest that A. humilis is derived from A. acaulis; the comparable levels of variability in the two species suggest that A. humilis was derived from a source containing a substantial portion of the original A. acaulis genome, because there is no evidence of a genetic bottleneck or appreciable loss of allelic variability.