1 online resource (98 pages) : PDF
University of North Carolina at Charlotte
Tissue regeneration and biomineralization are expressed to a diverse extent across metazoans and their life stages. The potential for repair and regrowth in adult stages varies widely within phyla, class and species. For instance, few adult human tissues can regenerate. In contrast, members of the phylum Echinodermata demonstrate remarkable regenerative capabilities. Holothuroids like the sea cucumber can regenerate vital organs after evisceration, while the echinoid sea urchin lacks this ability. Echinoderms have been model organisms for studies in embryonic developmental biology due to their abundant gametes and often clear embryos. More recently, adult echinoderms have emerged as models in regenerative studies. The ability of echinoderms to repair and regrow body parts as a response to injury or predation is valuable in studies of the basic mechanisms that underpin regeneration. The heterogeneity of regenerative capabilities within echinoderm classes provides insights into how regeneration is gained and lost. From an evolutionary standpoint, echinoderms share a common ancestor with chordates which include humans. Resolving the phylogenetic relationships of echinoderms provides a platform to understand the gain and loss of regeneration and may have future applications in medicine. Modern echinoderms occur in two major extant lineages, Crinozoa and Eleutherozoa. The evolutionary relationships within Eleutherozoa have remained ambiguous. The motivation for this dissertation is to resolve competing hypotheses in the evolutionary relationships within Eleutherozoa and examine competing hypotheses explaining the expansion of the msp130 family. The msp130 gene family is related to biomineralization - an important process in development and regeneration of echinoderms. I developed a novel analytical pipeline that produces phylogenetic trees from raw RNA-Seq data of 40 echinoderms. I also performed an analysis surveying the heterogenous regenerative capabilities across echinoderm classes by identifying enriched gene ontology terms that implicate biological processes of interest using class-specific datasets. Using a similar pipeline and the same transcriptome data I exploited to examine taxonomic relationships, my results provide support for an alternative hypothesis regarding the origin of the msp130 family within echinoderms. The phylogenetic analysis suggests that msp130 radiated from a deep common ancestral gene set via a complex series of organismal speciation and gene duplication events, rather than multiple independent instances of horizontal gene transfer.
Reid, RobertSchlueter, JessicaShi, XinghuaMarriott, Ian
Thesis (Ph.D.)--University of North Carolina at Charlotte, 2018.
This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s). For additional information, see http://rightsstatements.org/page/InC/1.0/.
Copyright is held by the author unless otherwise indicated.