Genetic structure and variability of the endemic and vulnerable Vellozia gigantea (Velloziaceae) associated with the landscape in the Espinhaço Range, in southeastern Brazil: implications for conservation

• Published in: Genetica 2011-04, Vol.139 (4), p.431-440
• Main Authors: Lousada, Júnia Maria, Borba, Eduardo Leite, Ribeiro, Katia Torres, Ribeiro, Leonardo Cotta, Lovato, Maria Bernadete
• Format: Article
• Language: English
• Subjects: Animal Genetics and Genomics; Bayes Theorem; Biomedical and Life Sciences; Brazil; Canyons; Cluster Analysis; Conservation of Natural Resources; Endemic species; Endemism; Evolutionary Biology; Gene Flow; Genetic diversity; Genetic structure; Genetic Variation - genetics; Geography; Human Genetics; Life Sciences; Magnoliopsida - genetics; Microbial Genetics and Genomics; Plant Genetics and Genomics; Species diversity; Species richness; Threatened species; Vegetation patterns; Velloziaceae
• ISSN: 0016-6707; 1573-6857
• DOI: 10.1007/s10709-011-9561-5

The Espinhaço Range, in eastern Brazil, has a peculiar landscape that has influenced the vegetation pattern of the region because of its valleys, canyons, ranges and disjunct rock outcrops found at high elevations. In this region, the vegetation type known as campos rupestres (rupestrian fields), which occurs in the disjunct outcrops, has high levels of species richness and endemism. Vellozia gigantea , a 6-m tall dracenoid monocot, is a vulnerable species endemic to this vegetation and has a narrow distribution that extends approximately 27 km. This region is located in a disturbed area, where populations are divided into three geographical groups, separated by a canyon and a valley. For this study, we used ISSR markers to measure the genetic diversity of the species and test the hypothesis that the canyon and the valley constitute geographical barriers to gene flow in V. gigantea . Nine populations and 173 individuals were analyzed using nine ISSR primers, which produced 89 fragments. In spite of being a vulnerable species with a narrow distribution, the populations of V. gigantea have high genetic diversity (mean percentage of polymorphic loci = 56.6%; mean Shannon’s index of diversity = 0.278; mean expected heterozygosity = 0.183). Genetic divergence among populations was high (Φ ST  = 0.28), and principal coordinate, neighborjoining and Bayesian analyses showed that only the canyon may constitute a partial barrier to gene flow in this species. Groups of populations separated by the canyon should be managed separately because they contain different gene pools.