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Phylogenomic, biogeography, and evolution of the ancient genus Isoetes with focus on the American clade

Grant number: 19/07109-4
Support type:Scholarships in Brazil - Post-Doctorate
Effective date (Start): September 01, 2019
Effective date (End): August 31, 2021
Field of knowledge:Biological Sciences - Botany
Principal Investigator:Jefferson Prado
Grantee:Jovani Bernardino de Souza Pereira
Home Institution: Instituto de Botânica. Secretaria do Meio Ambiente (São Paulo - Estado). São Paulo , SP, Brazil

Abstract

Phylogenetic inferences are being revolutionized with the emerging of the next-generation sequencing, which provides enormous amounts of gene sequence data. This data allows to clarify not only basal relationships, but also resolve rapid radiations that would be intractable with smaller datasets. This provides unprecedented opportunities to address fundamental evolutionary questions in intriguing plant groups such as the ancient genus Isoetes. The genus Isoetes is globally distributed with approximately 250 species. South America (SA) is one the centers of taxonomic diversity with 64 species. Phylogenetic studies revealed South American Isoetes species in two major clades: Gondwanian (from tropical areas in SA) and American (from subtropical to temperate areas in SA). American clade is the most diverse clade in Isoetes. Despite being well-supported, the relationships among the species within the American clade remain poorly understood. Polyploidy is a confounding factor in phylogenetic analyses and it hampers phylogenetic inferences in this group. Previous studies based on a few molecular regions led uncertainties in the deep and terminal relationships in the clade. The absence of a well-resolved phylogeny also hampered the capability of dating the divergence events and reconstructing the biogeographic history of the American clade. This research proposal aims to extend the sampling of species from crucial regions from South America, explore incongruence between nuclear and plastid phylogenies for the same set of taxa, explore the mechanisms which may be responsible for phylogenetic conflicts and determine the extension to which reticulation has influenced the evolution of American clade. The resulted phylogeny will be calibrated and the ancestral ranges of the species estimated to test biogeography hypotheses in the group. (AU)