Dissertation/Thesis Abstract

Insights into the taxonomy and evolution within an orchid, Platanthera dilatata, based on morphometrics and molecular markers
by Adhikari, Binaya, M.S., Mississippi State University, 2012, 70; 1516323
Abstract (Summary)

Documenting biodiversity, at and below the species level, is a persistently challenging task for biologists. Poor understanding of biodiversity may lead to incorrect interpretations of observed variation. The underlying basis of variation can be understood by quantifying multiple sources of information. Nine morphometric characters and plastid DNA sequences (2511 bps) were quantified in a highly variable orchid species, Platanthera dilatata, to evaluate taxonomy of the three named varieties and to understand patterns of evolution. Three morphological groups, identified in a cluster analysis, were distinct in multiple floral traits. Additionally, the three clusters were consistently genetically divergent as indicated by infrequent haplotype sharing, significantly different haplotype frequencies, and significant values of the genealogical sorting index. This level of genetic divergence suggests three species rather than varieties in this complex. The divergent floral morphologies suggest that pollinator-mediated selection may be a driving factor for speciation in this complex.

Indexing (document details)
Advisor: Wallace, Lisa E.
Commitee: Counterman, Brian, Welch, Mark E.
School: Mississippi State University
Department: Biological Sciences
School Location: United States -- Mississippi
Source: MAI 51/02M(E), Masters Abstracts International
Subjects: Ecology, Evolution and Development, Systematic
Keywords: AMOVA, GSI, Pollinator-mediated selection, Speciation, Species tree, UPGMA cluster
Publication Number: 1516323
ISBN: 978-1-267-54080-5
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