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The origins and maintenance of species boundaries in Jamesbrittenia O. Kuntze (Scrophulariaceae: Manuleae)

The genus Jamesbrittenia contains 83 species distributed throughout southern Africa. Many species produce attractive flowers and consequently their horticultural potential is currently being explored. Speciation patterns and reproductive isolation were investigated in order to identify trends that m...

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Main Author: Moncrieff, Glenn
Other Authors: Verboom, George Anthony
Format: Thesis
Language:English
Published: Department of Biological Sciences 2017
Subjects:
Botany
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access_status_str Open Access
author Moncrieff, Glenn
author2 Verboom, George Anthony
author_browse Moncrieff, Glenn
Verboom, George Anthony
author_facet Verboom, George Anthony
Moncrieff, Glenn
author_sort Moncrieff, Glenn
collection Thesis
description The genus Jamesbrittenia contains 83 species distributed throughout southern Africa. Many species produce attractive flowers and consequently their horticultural potential is currently being explored. Speciation patterns and reproductive isolation were investigated in order to identify trends that may apply at broader scales. Bayesian phylogenetic analysis was performed using plastid (rps 16 and psbA-trnH) and nuclear (GScp) sequence data. Relative divergence times were calculated using a relaxed clock method. Prezygotic isolation, measured as seed set resulting from interspecific crosses, correlated with divergence time. However, recently diverged, highly sympatric taxa deviated from the overall trend. This provides circumstantial evidence for reinforcement of reproductive barriers. Floral dissimilarity and divergence time were found to be useful in predicting hybridization reported in the wild (p<0.0001). Species pairs susceptible to hybridization were identified on the basis of their floral dissimilarity and divergence time in order to prevent potentially hybridizing species from being brought into contact. The inability to detect the dominant mode of speciation confounded interpretation of the results, as it was not possible to determine if the influence of geographic patterns on the evolution of reproductive isolation was a result of the mode of speciation or post-speciation evolutionary changes.
format Thesis
id oai:open.uct.ac.za:11427/26188
institution University of Cape Town (South Africa)
language eng
last_indexed 2026-06-10T12:32:00.945Z
license_str Not specified — see source repository
provenance_str_mv Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository
publishDate 2017
publishDateRange 2017
publishDateSort 2017
publisher Department of Biological Sciences
publisherStr Department of Biological Sciences
record_format dspace
source_str UCTD — University of Cape Town Open Access Repository
spelling oai:open.uct.ac.za:11427/26188 The origins and maintenance of species boundaries in Jamesbrittenia O. Kuntze (Scrophulariaceae: Manuleae) Moncrieff, Glenn Verboom, George Anthony Botany The genus Jamesbrittenia contains 83 species distributed throughout southern Africa. Many species produce attractive flowers and consequently their horticultural potential is currently being explored. Speciation patterns and reproductive isolation were investigated in order to identify trends that may apply at broader scales. Bayesian phylogenetic analysis was performed using plastid (rps 16 and psbA-trnH) and nuclear (GScp) sequence data. Relative divergence times were calculated using a relaxed clock method. Prezygotic isolation, measured as seed set resulting from interspecific crosses, correlated with divergence time. However, recently diverged, highly sympatric taxa deviated from the overall trend. This provides circumstantial evidence for reinforcement of reproductive barriers. Floral dissimilarity and divergence time were found to be useful in predicting hybridization reported in the wild (p<0.0001). Species pairs susceptible to hybridization were identified on the basis of their floral dissimilarity and divergence time in order to prevent potentially hybridizing species from being brought into contact. The inability to detect the dominant mode of speciation confounded interpretation of the results, as it was not possible to determine if the influence of geographic patterns on the evolution of reproductive isolation was a result of the mode of speciation or post-speciation evolutionary changes. 2017-11-13T08:51:30Z 2017-11-13T08:51:30Z 2007 2017-02-02T13:41:43Z Bachelor Thesis Honours BSc (Hons) http://hdl.handle.net/11427/26188 eng application/pdf Department of Biological Sciences Faculty of Science University of Cape Town
spellingShingle Botany
Moncrieff, Glenn
The origins and maintenance of species boundaries in Jamesbrittenia O. Kuntze (Scrophulariaceae: Manuleae)
thesis_degree_str Bachelor's / Honours
title The origins and maintenance of species boundaries in Jamesbrittenia O. Kuntze (Scrophulariaceae: Manuleae)
title_full The origins and maintenance of species boundaries in Jamesbrittenia O. Kuntze (Scrophulariaceae: Manuleae)
title_fullStr The origins and maintenance of species boundaries in Jamesbrittenia O. Kuntze (Scrophulariaceae: Manuleae)
title_full_unstemmed The origins and maintenance of species boundaries in Jamesbrittenia O. Kuntze (Scrophulariaceae: Manuleae)
title_short The origins and maintenance of species boundaries in Jamesbrittenia O. Kuntze (Scrophulariaceae: Manuleae)
title_sort origins and maintenance of species boundaries in jamesbrittenia o kuntze scrophulariaceae manuleae
topic Botany
url http://hdl.handle.net/11427/26188
work_keys_str_mv AT moncrieffglenn theoriginsandmaintenanceofspeciesboundariesinjamesbritteniaokuntzescrophulariaceaemanuleae
AT moncrieffglenn originsandmaintenanceofspeciesboundariesinjamesbritteniaokuntzescrophulariaceaemanuleae

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