Fine-Scale Genetic Structure ofZamia furfuracea: Variation with Life-Cycle Stages

Abstract

Fine-scale spatial genetic structure (SGS) analysis has proved to be a useful tool to establish the distribution of genetic variability between individuals and how these patterns are affected by microenvironmental conditions, associations with pollinators and dispersers, and sex ratio. In this study, the correlation between the fine-scale SGS of a population of Zamia furfuracea L. fil. and its dependence on the patterns of spatial aggregation between categories of life cycle and the proportion of males and females was determined by using intersimple sequence repeat markers. Results showed an aggregation pattern dependent on reproductive adults of up to 10 m; however, dependence on sex was restricted to only 3 m, suggesting limited pollen and seed dispersal. Gene neighborhoods did not exceed 10 m, with three well-defined families within the population. The small size of the neighborhoods, high mortality rate of seedlings, and loss of genetic variability in the juvenile category suggest that this population is severely affected. Our results contribute to the understanding of genetic and spatial dynamics in natural populations of cycads. Such information should be considered for the implementation of ex situ population-management programs.