The frozen-niche-variation model was proposed to account for the coexistence of ge­netically related clones in naturally occurring unisexual populations. This model is based on two assumptions: 1) ecologically different clones have multiple independent origins from sexual ances­tors; and 2) the population of sexual ancestors contains genetic variability for ecologically relevant traits. To test these assumptions, we produced 14 new "hemiclones" (nonrecombining haploid genotypes) offish (Poeci!iopsis: Poeciliidae). Our ability to synthesize many new hemiclones dem­onstrates the feasibility of multiple independent origins of nonrecombining genotypes. A substantial proportion (I 0-50%) of the phenotypic variation among hemiclones in size at birth,juvenile growth rate, and fecundity had a genetic basis. Thus, we conclude that multiple origins can give rise to an assemblage of genetically distinct hemiclones, each with a unique combination of life-history traits. Additionally, a comparative analysis of two natural hemiclones revealed that the synthetic strains represent a broad field of variation from which natural hemiclones can be selected.