2010
ASM Conference, Mobile DNA, April 24 - 28, 2010, Montreal, Canada
27 Apr 2010 When Repeats Meet Chromatin: Relationship Between Repeats and Heterochromatin DynamicsH. Quesneville, A. Fiston-Lavier, C. Vejnar
Heterochromatin is typically highly condensed and enriched in repeats such as DNA tandem repeat arrays, transposable elements (TEs) and segmental duplications. A key feature of heterochromatin is its ability to propagate, and thereby to influence gene expression. Three types of heterochromatic regions have been described: the centromeres, the telomeres and the ‘knobs’ - i.e. interstitial heterochromatin regions -.To understand the relationship between repeats and chromatin structure, we investigated the repeat evolutionary dynamics in A. thaliana by comparing their features in heterochromatin and euchromatin domains. We constructed phylogenetic trees of repeats to estimate their dynamics in these two chromatic domains. The heterochromatic repeats appear younger and longer than those located into the euchromatin. We estimated the strengths of elimination of these sequences to understand this surprising result. We then propose a model of TE dynamics where gene selection pressure and non-allelic homologous recombination shape genome structure. The study of the TEs dynamics in the heterochromatic domains such as the pericentromere is an excellent opportunity to also compare TE dynamics in genome having low or high TE density. Hence, we could make several predictions, helpful for TE annotation of repeat rich genomes.
Keywords: Transposable elements, Heterochromatine, genome structure
Creation date: 03 May 2010
eZ PublishPublication supervisor: A-F. Adam-Blondon
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