New insights into the evolutionary history of the complex andean genus polylepis (Rosaceae: sanguisorbeae) and implications for conservation and management
- Authors
- Segovia Salcedo, Mar?a Claudia
- Format
- MasterThesis
- Status
- publishedVersion
- Description
The genus Polylepis comprises approximately 28 species, found excusively in the high Andes growing up to 4400 m above sea level. Polylepis forests play a fundamental role in the hydrological equilibrium of the highlands and create refuges for endemic flora and fauna. Human activities have restricted their distribution, and now Polylepis forests are considered one of the most threatened neo-tropical ecosystems. In the last few decades, the genus has been the object of intensive study to understand many aspects of its natural history and ecology. However, many areas related to the evolution and systematics remain unclear due to hybridization and polyploidy; therefore, this research focuses on clarifying the evolutionary history of Polylepis in the Andes. I analyzed 256 nuclear genes and chloroplast genomes of 25 ingroup taxa using Next-Generation Sequencing (Hyb-Seq). The analyses support the complex evolutionary history of Polylepis and provide new insights about interspecific relationships. The results of the phylogenomic study greatly increase confidence in relationships over prior phylogenetic analyses of Polylepis. The status of cytogenetic studies in Polylepis was 15 evaluated. Chromosome counts for 146 individuals representing 8 species of Polylepis are reported. Genome sizewas also estimated, and two cytotypes were detected in several species (P. racemosa and P. sericea). Genome size and chromosome number are correlated in the Ecuadorian species of Polylepis, and three ploidies were detected: 6x (2n~42), 10x (2n~72), and 12x (2n~82). Chromosome counts, chromosome evolution models and flow cytometry results support the hypothesis that polyploidy and hybridization have played prominent roles in the evolution of this Andean tree. Finally, eight polymorphic dinucleotide microsatellite loci isolated from Polylepis racemosa are described, and I document their utility in the analysis of population differentiation and genetic diversity thoughout Polylepis.
- Publication Year
- 2014
- Language
- eng
- Topic
- CITOGEN?TICA
FILOGEN?MICA
GEN?TICA POBLACIONAL
CONSERVACI?N
- Repository
- Repositorio SENESCYT
- Rights
- openAccess
- License
- openAccess