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R1 Retrotransposons In Drosophila Melanogaster Are Transcribed By Rna Polymerase I Upon Heat Shock, Himanshu Shekhar Raje

LSU Doctoral Dissertations

The ribosomal RNA genes of Drosophila melanogaster reside within centromere-proximal nucleolar organizers on both the X and Y chromosomes. Each locus contains between 200-300 tandem repeat rDNA units that encode 18S, 5.8S, and 28S ribosomal RNAs (rRNAs) for ribosome biogenesis. In arthropods like Drosophila, about 60% of rDNA genes are inserted with R1 and/or R2 retrotransposons at specific sites within the 28S regions; these units likely fail to produce functional 28S rRNA. We showed previously that R2 expression increases upon nucleolar stress caused by the loss of a ribosome assembly factor, the Nucleolar Phosphoprotein of 140 kDa (Nopp140). Here …

An Analysis Of Alu Elements In Baboons, Cody James Steely

LSU Doctoral Dissertations

Transposable elements compose a large portion of mammalian genomes and are estimated to make up anywhere from ~45% - ~70% of the human genome. Alu elements are primate-specific retrotransposons that are found in high copy number (> 1 million copies) and are spread throughout the genome. These elements are the most commonly repeated sequence in the human genome and have contributed to a number of disease states in humans. Alu elements are useful markers for population genetics and phylogenetics and have proven valuable in understanding difficult to determine relationships between species and within populations.

Baboons (genus Papio) are spread throughout …