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    A Comparative Study Mapping the Landscape of Repetitive Elements in Fundulus heteroclitus
    (Wheaton College. (Norton, Mass.), 2021-05-16) Elkhoury, Kevin
    Fundulus heteroclitus has shown to be capable of rapid adaptation in environments lethal to most other species. Comparisons of isolated Fundulus heteroclitus populations in similar polluted environments have been found to contain similar mutations despite their geographic isolation. This thesis aims to identify the potential role transposable elements serve in Fundulus heteroclitus relating to these common mutations. To accomplish this a pipeline is created that annotate genomes for transposable elements and is applied to the Fundulus heteroclitus genome to be used for further study.
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    Evolution and diversification in toll-like receptors of fundulus heteroclitus and teleosts based on whole genomic data.
    (Wheaton College (MA), 2019) Wu, Yusheng
    Toll-like receptors (TLRs) are a major component of the innate immune system and are pivotal for organismal survival by recognizing a diverse group of pathogens. Compared to mammals, TLRs are found to be more diverse in teleost species, which suggests the essential role of innate immunity in teleosts due to the lack of their diversification in adaptive immunity.The purpose of this study was, 1) to estimate an evolutionary tree of teleosts TLRs, 2) to verify and clarify the number of TLR gene copies in Fundulus heteroclitus, and 3) to test for evidence of positive selection acting on the various TLRs. A gene tree of the TLR family in teleosts was constructed based on the whole genome data from Ensembl database, and it allowed for a clarification in teleost TLRs’ nomenclature and the description of the full complement of TLRs in F. heteroclitus.Positively selected sites were detected in all TLRs with TLR22 found to be under the highest positive selection rate (4.63% of TLR gene sites) among all TLRs. Copy number variation of teleost-specific TLR22 gene moreover suggested gene duplication and diversification potentially to compensate for the lack of other cell surface TLRs. These results suggested that various TLR22 paralogues have likely arisen from positive selection pressure as well as gene expansion and functional diversification in teleost species.
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    Analysis of ciliary gene expression in sea urchin development.
    (Wheaton College (MA), 2019) Olander, Kira E.
    Cilia are important cellular organelles tied to many disease states due to their pivotal roll in important cellular processes, including early organism development. In this Honors Thesis, cilia were studied in developing Strongylocentrotus purpuratus embryos during the blastula stage of development. The blastula stage is when the sea urchin embryos develop motile cilia. The upstream DNA regions of 37 ciliary genes expressed during the blastula stage of development were analyzed using a motif discovery algorithm MEME and further analyzed with a motif comparison algorithm TOMTOM, in search of shared regulatory elements related to transcription factor binding proteins. This experiment resulted in three promising motifs aligned with known transcription factors Klf6, Klf11, Klf2, and Glis-3. Our data supports a model were Klf6, Klf11, and Klf2 may be transcriptional enhancers of the blastula cluster genes while Glis-3 may be a transcriptional repressor. These transcription factor proteins may play a roll in regulating the ciliary phenotype in S.p..
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    Genomics approaches to analyzing ciliary gene functions and regulation.
    (Wheaton College (Norton, Mass.), 2016) Mullings, Javon R.
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    Evidence for selection of toll-like receptors in Atlantic killifish Fundulus heteroclitus.
    (Wheaton College (Norton, Mass.), 2014) Soucier, Devon.
    Toll-like receptors (TLRs) are a multigene family whose function is critical to the innate immune system in invertebrates and vertebrates. Variation within TLR gene regions may be a reflection of environment and pathogen co-evolution. The purpose of this study is to evaluate the level of genomic variation at TLR 5, 9, and 21 of Atlantic killifish Fundulus heteroclitus. Atlantic killifish have been studied extensively because of their ability to survive in variable environments that may be breeding grounds for varying populations of pathogens. The study looked at four populations of killifish from northern Maine. Sites included one copper contaminated locale and three other presumably uncontaminated environments. Average heterozygosity was calculated for all individuals at the gene regions. The results suggested that little variation was evident in the exon region of TLR 5. However, more variation was seen at the exon regions of TLR 9 and 21, as well as, the 5'UTR of TLR 9. Variation amongst the four populations was also detected. These results suggest that variation does exist at TLR 5, 9, and 21, however further studies need to be completed in order to gauge the implications of this variation.