Spatial Distributions of Cytoplasmic Types and Sex Expression in Alaskan Populations ofSilene acaulis

Abstract

Sex expression in gynodioecious plants is often governed by an interaction between maternally inherited cytoplasmic male sterility (CMS) genes and nuclear male fertility restorer genes. Previous studies have documented an association between females and maternally inherited molecular markers in the cytoplasmic genomes in natural populations, suggesting that these markers are associated with different CMS types. We analyzed the spatial distributions of mitochondrial and chloroplast alleles and the sexual phenotype of individuals within five Alaskan populations of Silene acaulis. Within two populations, mitochondrial alleles, but not sex, were clustered at a scale ≤2 m. We suggest that this pattern is generated by short‐distance dispersal of mitochondrial alleles (and CMS) through seed and longer‐distance dispersal of nuclear restorers through both pollen and seed. We also investigated whether the association between mitochondrial alleles and sex ratio changed through time (across size classes), as might be...