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Title page for ETD etd-10222008-144721


Type of Document Dissertation
Author Ellis, Jennifer Rhea
Author's Email Address jennifer.ellis@vanderbilt.edu
URN etd-10222008-144721
Title Conservation genetics of the endangered sunflower Helianthus verticillatus
Degree PhD
Department Biological Sciences
Advisory Committee
Advisor Name Title
Terry L. Page Committee Chair
Carol J. Baskauf Committee Member
Daniel J. Funk Committee Member
David E. McCauley Committee Member
John M. Burke Committee Member
Patrick Abbot Committee Member
Keywords
  • Sunflowers -- Genetics
  • population genetics
  • fitness
  • rare
  • population size
  • outbreeding depression
  • F2
  • expressed sequence tags
  • SSRs
  • heteroplasmy
  • microsatellites
  • Sunflowers -- Conservation
  • Plant population genetics
  • Endangered plants
Date of Defense 2008-10-03
Availability unrestricted
Abstract
One of the greatest factors contributing to the worldwide decline in biodiversity is habitat destruction leading to the loss and fragmentation of populations of many species. Knowledge of the genetic and demographic factors that are affected by and influence rarity advances our understanding of the consequences of habitat degradation, and this knowledge is crucial for creating management plans for rare or endangered species. In this dissertation, I address these factors in a rare sunflower species, Helianthus verticillatus, through studies of its population genetics and taxonomic status, the assessment of population size, and the evaluation of fitness. A population genetic study, employing a novel genetic marker, demonstrated that this species is not the product of recent hybridization and, surprisingly, harbors high levels of genetic diversity despite its small number of populations and disjunct range. A study of the clonal diversity and structure in this species revealed far fewer numbers of individuals than were previously reported; these results led to the upgrading of the speciesí priority status for the Endangered Species Act. Finally, populations differed with respect to phenotypic fitness related traits; this was not predicted by population genetic data and further highlights the need for comprehensive studies of endangered species in order to fully evaluate the effects of rarity and fragmentation on population viability.

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