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Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học Wertheim cung cấp cho các bạn kiến thức về ngành y đề tài: Dosage compensation and the global re-balancing of aneuploid genomes. | Prestel et al. Genome Biology 2010 11 216 http genomebiology.eom 2010 11 8 216 w Genome Biology REVIEW Dosage compensation and the global re-balaneing of aneuploid genomes Matthias Prestel Christian Feller and Peter B Becker Abstract Diploid genomes are exquisitely balanced systems of gene expression. The dosage-compensation systems that evolved along with monosomic sex chromosomes exemplify the intricacies of compensating for differences in gene copy number by transcriptional regulation. Complex genomes are more than just the sum of their genes but are rather complex regulatory systems in which the expression of each individual gene is a function of the activity of many other genes so that the levels of their protein products are maintained within a narrow range. Such homeostasis favors the maintenance of the appropriate stoichiometry of subunits in multiprotein complexes or of components in signal transduction pathways and defines the ground state of a cell 1 . In diploid genomes both alleles of a gene are usually active and this double dose of each gene is figured into the equation. Thus deviations from diploidy such as the deletion or duplication of genes or of larger chromosomal fragments aneuploidy unbalance the finely tuned expression of the genome. Segmental aneuploidies of this kind can arise from failed or faulty repair of chromosomal damage due to irradiation chemical insult or perturbation of replication or from illegitimate recombination during meiosis. Loss or duplication of entire chromosomes monosomy or trisomy respectively can arise from nondisjunction during cell division. Depending on the extent of the aneuploidy and on the genes affected the fine balance of trans-acting factors and their chromosomal binding sites that define the gene-expression system is disturbed and the fitness of the cell or organism challenged. Often aneuploidies have been associated with a variety of developmental defects and malignant aberrations Correspondence .
