Genetic structure of Hepatica nobilis var. japonica, focusing on within population flower color polymorphism.

How phenotypic or genetic diversity is maintained in a natural habitat is a fundamental question in evolutionary biology. Flower color polymorphism in plants is a common polymorphism. Hepatica nobilis var. japonica on the Sea of Japan (SJ) side of the Japanese mainland exhibits within population flower color polymorphism (e.g., white, pink, and purple), while only white flowers are observed on the Pacific Ocean (PO) side. To determine the relationships between flower color polymorphism, within and among populations, and the genetic structure of H. nobilis var. japonica, we estimated the genetic variation using simple sequence repeat (SSR) markers. First, we examined whether cryptic lineages corresponding to distinct flower colors contribute to the flower color polymorphisms in H. nobilis var. japonica. In our field observations, no bias in color frequency was observed among populations on Sado Island, a region with high variation in flower color. Simple sequence repeat (SSR) analyses revealed that 18% of the genetic variance was explained by differences among populations, whereas no genetic variation was explained by flower color hue or intensity (0% for both components). These results indicate that the flower color polymorphism is likely not explained by cryptic lineages that have different flower colors. In contrast, populations in the SJ and PO regions were genetically distinguishable. As with the other plant species in these regions, refugial isolation and subsequent migration history may have caused the genetic structure as well as the spatially heterogeneous patterns of flower color polymorphisms in H. nobilis var. japonica.

Development of polymorphic microsatellite loci in the perennial herb Hepatica nobilis var. japonica (Ranunculaceae).

PREMISE OF THE STUDY: Microsatellite markers were developed and characterized in the vulnerable plant Hepatica nobilis var. japonica (Ranunculaceae) to investigate its genetic diversity, population structure, and gene flow. METHODS AND RESULTS: Fourteen microsatellite markers were developed. The number of alleles per locus ranged from one to 12, and the expected heterozygosity per locus ranged from 0.043 to 0.855. Eleven markers were successfully amplified in the cultivar 'Mego' from Japan. CONCLUSIONS: These microsatellite markers can be used to investigate the genetic diversity, population structure, and gene flow of H. nobilis var. japonica.