Please use this identifier to cite or link to this item: http://hdl.handle.net/10125/66254

PHYLOGENETICS AND EVOLUTION OF OREOGRAMMITIS, RADIOGRAMMITIS AND THEMELIUM (POLYPODIACEAE) AND POPULATION GENETICS OF HAWAIIAN ENDEMIC OREOGRAMMITIS HOOKERI AND ADENOPHORUS TRIPINNATIFIDUS

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Title:PHYLOGENETICS AND EVOLUTION OF OREOGRAMMITIS, RADIOGRAMMITIS AND THEMELIUM (POLYPODIACEAE) AND POPULATION GENETICS OF HAWAIIAN ENDEMIC OREOGRAMMITIS HOOKERI AND ADENOPHORUS TRIPINNATIFIDUS
Authors:Sirimalwatta, Vithanage Nipuni Shalika
Contributors:Morden, Clifford W. (advisor)
Ranker, Thomas A. (advisor)
Botany (department)
Keywords:Botany
Systematic biology
Date Issued:2019
Publisher:University of Hawaiʻi at Mānoa
Abstract:Grammitids are a large monophyletic group of primarily epiphytic ferns in Polypodiaceae. Genera Oreogrammitis, Radiogrammitis and Themelium (ORT) formed a clade in grammitid phylogeny where three genera are polyphyletic in the ORT clade. A study was conducted to delineate the phylogenetic relationships of the ORT group by using intensive taxon sampling and with nine genetic markers from both nuclear and chloroplast genomes. Gene sequences were analyzed in maximum likelihood and Bayesian algorithms. Nuclear gene trees and nuclear and plastid gene trees were summarized to construct species trees under multi-species coalescent method in ASTRAL program. All the analyses with higher number of species and data revealed that the three genera are polyphyletic. Thus, taxonomic revisions are suggested. Oreogrammitis must be redefined to include Radiogrammitis and Themelium.
Oreogrammitis hookeri is an endemic Hawaiian grammitid fern. It is one of the three Hawai‘i endemic Oreogrammitis species. Oreogrammitis hookeri can be found in all the major islands in Hawaiian archipelago whereas the other two species have limited distribution. Some populations of O. hookeri contain unique alleles and the species may have been undergoing incipient speciation or represent cryptic species complex. Current study was conducted to investigate the population structure of O. hookeri with populations sampled from all the major islands except Lanai. Double Digest Restriction Site Associated DNA sequencing (ddRADseq) technique was used to generate genomic data. Analysis of 176 loci in STRUCTURE program showed that there are two genotypes in O. hookeri. Populations collected from Kauaʻi and Mauna Loa, Hawai‘i is one genotype and Oʻahu and Kilauea, Hawai‘i is another genotype. Maui and Molokaʻi contain both genotypes. Incipient speciation or existence of cryptic species of O. hookeri can be ruled out because Maui-Molokaʻi genetic cluster contain both genotypes thus it supports the idea that individuals from all sampling localities are part of one interbreeding lineage. Genetic differences among populations could simply be due to random processes such as founder effects although localized adaptation cannot be ruled out.
Genus Adenophorus is one of the two endemic fern genera in Hawai‘i. The genus consisted of ten species. Adenophorus tripinnatifidus is highly variable species. A population study done on A. tripinnatifidus showed low levels of interpopulational gene flow when compared to its conspecific, A. tamariscinus, species. The present study conducted to explore the genetic structure of A. tripinnatifidus. Samples collected from Kauaʻi, Maui and Molokaʻi. DNA samples of 35 samples from four populations were sequenced using ddRADseq technique. Hundred and forty-four loci were analyzed in STRUCTURE. Two genotypes were recovered. Kauaʻi populations are genetically distinct from Maui and Molokaʻi populations. Thus, it can be inferred that A. tripinnatifidus is undergoing incipient speciation.
Pages/Duration:170 pages
URI:http://hdl.handle.net/10125/66254
Rights:All UHM dissertations and theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission from the copyright owner.
Appears in Collections: Ph.D. - Botany


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