Molecular systematics and organellar genomics of the green macroalgal genus Ulva (Ulvophyceae, Chlorophyta) with a phylogenomic analysis of the "core Chlorophyta"

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dc.contributor Lam, Daryl W.
dc.contributor Olson, Julie B.
dc.contributor Powell, Martha J.
dc.contributor Wysor, Brian
dc.contributor.advisor Lopez-Bautista, Juan M. Melton III, James Theodore 2017-07-28T14:12:42Z 2017-07-28T14:12:42Z 2017
dc.identifier.other u0015_0000001_0002664
dc.identifier.other MeltonIII_alatus_0004D_13090
dc.description Electronic Thesis or Dissertation
dc.description.abstract The green macroalgal genus Ulva (Ulvophyceae, Chlorophyta) is found worldwide in varying salinities and water depths.Ulva species are ecologically and economically important, and are known to be taxonomically troublesome due to their simple morphology, cryptic speciation, and morphological plasticity. For this study, DNA sequence data from these algae from molecularly understudied areas such as the U.S. Southeast and Gulf Coast, Panama, Chile, and Tenerife, Canary Islands, Spain, revealed an unexpected diversity consisting of several new reports and up to nine undescribedUlva species. One new report for the Western Atlantic,Ulva ohnoi Hiraoka & Shimada, 2004, has begun to form overgrowths in southern Florida and Texas, and has likely been introduced and is potentially invasive in this area. In another aspect of this research, next generation sequence data are providing insights into the organellar genome evolution and phylogenomics of the “core Chlorophyta”. Here, we analyzed the chloroplast (cpDNA) and mitochondrial (mtDNA) genomes of Ulva fasciata and Ulva sp. UNA00071828. Both cpDNAs were similar in size (99,983 bp in U. sp. versus 96,005 bp in Ulva fasciata ). Both of these genomes were gene compact with 102 genes (71 protein-coding genes, 28 transfer RNAs [tRNAs], and three ribosomal RNAs [rRNAs]), AT-rich, and lacked an inverted repeat. A syntenic comparison of the two genomes showed that a ~27,000 bp segment of DNA that contains 46 genes was inverted. The variance in size of the mitochondrial genomes of Ulva fasciata (61,614 bp) and Ulva sp. (73,493 bp) was mostly due to more introns being present in Ulva sp. (ten introns) than U. fasciata (four introns). These mtDNAs followed the “expanded” pattern also seen in other ulvophyceans and trebouxiophyceans. Fifty-six genes were annotated in both genomes (29 protein-coding genes, 25 tRNAs, and two rRNAs). Phylogenomic analyses of both chloroplast and mitochondrial protein-coding genes showed no support for a monophyletic Ulvophyceae. These results contrast with the traditional classification of Chlorophyta at the class level. However, further taxon sampling is needed before any major taxonomic revisions are considered. This dissertation research has provided a systematic and genomic framework for future studies on Ulva .
dc.format.extent 428 p.
dc.format.medium electronic
dc.format.mimetype application/pdf
dc.language English
dc.language.iso en_US
dc.publisher University of Alabama Libraries
dc.relation.ispartof The University of Alabama Electronic Theses and Dissertations
dc.relation.ispartof The University of Alabama Libraries Digital Collections
dc.relation.hasversion born digital
dc.rights All rights reserved by the author unless otherwise indicated.
dc.subject.other Biology
dc.subject.other Molecular biology
dc.subject.other Plant sciences
dc.title Molecular systematics and organellar genomics of the green macroalgal genus Ulva (Ulvophyceae, Chlorophyta) with a phylogenomic analysis of the "core Chlorophyta"
dc.type thesis
dc.type text University of Alabama. Dept. of Biological Sciences Biological Sciences The University of Alabama doctoral Ph.D.

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