6 resultados para COPY-NUMBER VARIATIONS

em Brock University, Canada


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There are many known taste receptors specific to each taste attribute. This thesis examines the relationship between single nucleotide polymorphisms (SNPs) and copy number variations (CNVs) in known taste and taste pathway receptors TAS2R38, Gustin, and TRPM5 and for PROP (6-n-propylthiouracil) taster status (PTS), thermal taster status (TTS), and orosensory sensation intensity ratings. PTS is a proxy for general taste responsiveness, and the ability to taste PROP classifies individuals into three phenotypes: super (PST), medium (PMT), and non-tasters (PNT). Another taste phenotype, also serving as a proxy for general taste responsiveness, is TTS, classifying individuals as thermal tasters (TTs) or thermal non-tasters (TnTs). DNA extractions from buccal cells obtained from 60 individuals were performed and analysis of TAS2R38, Gustin, and TRPM5 variations were conducted through Polymerase Chain Reaction (PCR), sequencing for SNPs, and upQMPSF for CNV analysis of TRPM5. Among the SNPs and CNVs studied, only TAS2R38 was found to be significantly associated with PTS and intensity ratings for sweet, bitter, and sour taste as well as astringency. However, not all PROP phenotypic differences can be explained by the variations at these three SNP sites in TAS2R38, suggesting the involvement of additional genes. No association was found between TTS and TAS2R38 or Gustin, confirming that PTS and TTS are not genetically associated. The examined TRPM5 SNPs and CNVs did not correlate with TTS. Therefore, further research is necessary into other factors contributing to PTS and TTS.

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The regenerating urodele limb is a useful model system in which to study, in vivo, the controls of cell proliferation and differentiation. Techniques are available which enable one to experimentally manipulate mitogenic influences upon the blastema, as well the morphogenesis of the regenerating 11mb. Although classical regeneration studies have generated a wealth of knowledge concerning tissue interactions, little 1s known about the process at the level of gene expression. The aim of this project was to clone potentially developmentally regulated genes from a newt genomic library for use in future studies of gene expression during limb regeneration. We decided to clone the cytoskeletal actin gene for the following reasons: 1. its expression reflects the proliferative and differentiatlve states of cells in other systems 2. the high copy number of cytoplasmic actin pseudogenes in other vertebrates and the high degree of evolutionary sequence conservation among actin genes increased the chance of cloning one of the newt cytoplasmic actin genes. 3. Preliminary experiments indicated that a newt actin could probably be identified using an available chick ~-actln gene for a molecular probe. Two independent recombinant phage clones, containing actin homologous inserts, were isolated from a newt genomic library by hybridization with the chick actin probe. Restriction mapping identified actin homologous sequences within the newt DNA inserts which were subcloned into the plasmid pTZ19R. The recombinant plasmids were transformed into the Escherichia coli strain, DHsa. Detailed restriction maps were produced of the 5.7Kb and 3.1Kb newt DNA inserts in the plasmids, designated pTNAl and pTNA2. The short «1.3 Kb) length of the actin homologous sequence in pTNA2 indicated that it was possibly a reverse transcript pseudogene. Problems associated with molecular cloning of DNA sequences from N. viridescens are discussed with respect to the large genome size and abundant highly repetitive DNA sequences.

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Identification of larval simuliids has always been difficult due to the morphological similarity many species bear to one another. For this reason all characters available have been drawn upon to aid in species identification, including head fan ray number. Even in light of an increasing body of anecdotal reports that head fan ray number is not fixed, it has continued to be used to aid species identification. In the current experiment simuliid larvae were reared under controlled laboratory conditions to last instar in one of three feeding regimes. Out of nine trials, the results of six showed a significant inverse relationship between feeding regime and head fan ray number. In addition to the laboratory experiments, larvae were also collected from the field over the course of the spring and summer, 1994. From these samples significant interspecific and intraspecific variations in head fan ray number were found both spatially and temporally within Algonquin Park. From these data it is concluded that head fan ray number for the species analysed is a developmentally plastic character, which varies in response to food availability. Furthermore, given the extreme variations in head fan ray number found in some species, I recommend that head fan ray number not be used as an aid to identification unless it can be shown to be a fixed character for the species in question.

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Joseph Pope was born in Charlottetown, Prince Edward Island in 1854. He was the private secretary to Sir John A. Macdonald from 1882-1891. He worked as the assistant clerk to the Privy Council and undersecretary of state for Canada from 1896-1909. He was appointed a Companion of the Order of St. Michael and St. George in 1901. He was later knighted as a Knight Commander of the same order. Joseph Pope was the first permanent head of the Department of External Affairs (now Foreign Affairs and Internal Trade) 1909-1925. He was an advisor to Prime Ministers from Macdonald to King. He died in Ottawa, in 1926. As well as Confederation, Pope also penned: Memoirs of Sir John A. Macdonald : A Chronicle of the First Prime Minister of the Dominion; The Day of Sir John Macdonald; Jacques Cartier, his life and voyages; Traditions and Sir John A. MacDonald vindicated : a review of the Right Honourable Sir Richard Cartwright's reminiscences as well as other books Pope’s son, Maurice Arthur Pope wrote a book about Joseph entitled Public Servant: the Memoirs of Sir Joseph Pope”.

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Genome sequence varies in numerous ways among individuals although the gross architecture is fixed for all humans. Retrotransposons create one of the most abundant structural variants in the human genome and are divided in many families, with certain members in some families, e.g., L1, Alu, SVA, and HERV-K, remaining active for transposition. Along with other types of genomic variants, retrotransponson-derived variants contribute to the whole spectrum of genome variants in humans. With the advancement of sequencing techniques, many human genomes are being sequenced at the individual level, fueling the comparative research on these variants among individuals. In this thesis, the evolution and functional impact of structural variations is examined primarily focusing on retrotransposons in the context of human evolution. The thesis comprises of three different studies on the topics that are presented in three data chapters. First, the recent evolution of all human specific AluYb members, representing the second most active subfamily of Alus, was tracked to identify their source/master copy using a novel approach. All human-specific AluYb elements from the reference genome were extracted, aligned with one another to construct clusters of similar copies and each cluster was analyzed to generate the evolutionary relationship between the members of the cluster. The approach resulted in identification of one major driver copy of all human specific Yb8 and the source copy of the Yb9 lineage. Three new subfamilies within the AluYb family – Yb8a1, Yb10 and Yb11 were also identified, with Yb11 being the youngest and most polymorphic. Second, an attempt to construct a relation between transposable elements (TEs) and tandem repeats (TRs) was made at a genome-wide scale for the first time. Upon sequence comparison, positional cross-checking and other relevant analyses, it was observed that over 20% of all TRs are derived from TEs. This result established the first connection between these two types of repetitive elements, and extends our appreciation for the impact of TEs on genomes. Furthermore, only 6% of these TE-derived TRs follow the already postulated initiation and expansion mechanisms, suggesting that the others are likely to follow a yet-unidentified mechanism. Third, by taking a combination of multiple computational approaches involving all types of genetic variations published so far including transposable elements, the first whole genome sequence of the most recent common ancestor of all modern human populations that diverged into different populations around 125,000-100,000 years ago was constructed. The study shows that the current reference genome sequence is 8.89 million base pairs larger than our common ancestor’s genome, contributed by a whole spectrum of genetic mechanisms. The use of this ancestral reference genome to facilitate the analysis of personal genomes was demonstrated using an example genome and more insightful recent evolutionary analyses involving the Neanderthal genome. The three data chapters presented in this thesis conclude that the tandem repeats and transposable elements are not two entirely distinctly isolated elements as over 20% TRs are actually derived from TEs. Certain subfamilies of TEs themselves are still evolving with the generation of newer subfamilies. The evolutionary analyses of all TEs along with other genomic variants helped to construct the genome sequence of the most recent common ancestor to all modern human populations which provides a better alternative to human reference genome and can be a useful resource for the study of personal genomics, population genetics, human and primate evolution.

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Copy of a report of a Committee of the Honorable and Executive Council dated May 6, 1859 approved by His Excellency the Governor General in Council. This is in regard to charges made by Joshua Manly of Port Colborne against Mr. Woodruff, the superintendent and other persons connected with the Welland Canal. The accusations have been substantiated by the committee. This is accompanied by a petition accusing Mr. Woodruff of gross corruption and jobbery [the practice of using a public office or position of trust for one's own advantage]. This was signed by a number of petitioners on July 2, 1858 (2 pages, handwritten), 1859.