Evolutionary Relationships, Gynodioecy, and Polyploidy in the Galápagos EndemicLycium minimum(Solanaceae)

Premise of research. Whereas most Lycium species are diploid and hermaphroditic, an association across Lycium species has been demonstrated between higher ploidy levels and gender dimorphism. Previous monographic work, in combination with a single tetraploid chromosome count, suggested that the Galapagos endemic Lycium minimum may be dimorphic. If substantiated, this would be the only documented Lycium species from South America to be dimorphic in gender expression, which is especially notable given that species diversity is highest in South America. The goals of this study are to (1) test the monophyly, characterize population-level genetic diversity, and determine the closest mainland relatives of L. minimum; (2) infer the sexual system of L. minimum; and (3) assess/verify ploidy using DNA content measurements.Methodology. Phylogenetic, morphological, and cytometric approaches were used to document evolutionary affinities, gynodioecy, and polyploidy. Phylogenetic analyses were conducted with DNA sequenc...