TY - JOUR A1 - Ji, Yonggang A1 - Eichler, Evan E. A1 - Schwartz, Stuart A1 - Nicholls, Robert D. T1 - Structure of Chromosomal Duplicons and their Role in Mediating Human Genomic Disorders Y1 - 2000/05/01 JF - Genome Research JO - Genome Research SP - 597 EP - 610 DO - 10.1101/gr.10.5.597 VL - 10 IS - 5 UR - http://genome.cshlp.org/content/10/5/597.abstract N2 - Chromosome-specific low-copy repeats, or duplicons, occur in multiple regions of the human genome. Homologous recombination between different duplicon copies leads to chromosomal rearrangements, such as deletions, duplications, inversions, and inverted duplications, depending on the orientation of the recombining duplicons. When such rearrangements cause dosage imbalance of a developmentally important gene(s), genetic diseases now termed genomic disorders result, at a frequency of 0.7–1/1000 births. Duplicons can have simple or very complex structures, with variation in copy number from 2 to >10 repeats, and each varying in size from a few kilobases in length to hundreds of kilobases. Analysis of the different duplicons involved in human genomic disorders identifies features that may predispose to recombination, including large size and high sequence identity between the recombining copies, putative recombination promoting features, and the presence of multiple genes/pseudogenes that may include genes expressed in germ cells. Most of the chromosome rearrangements involve duplicons near pericentromeric regions, which may relate to the propensity of such regions to accumulate duplicons. Detailed analyses of the structure, polymorphic variation, and mechanisms of recombination in genomic disorders, as well as the evolutionary origin of various duplicons will further our understanding of the structure, function, and fluidity of the human genome. ER -