tailieunhanh - Báo cáo y học: "otspots of homologous recombination in the human genome: not all homologous sequences are equal"

Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học quốc tế cung cấp cho các bạn kiến thức về ngành y đề tài: Hotspots of homologous recombination in the human genome: not all homologous sequences are equal. | Minireview Hotspots of homologous recombination in the human genome not all homologous sequences are equal James R Lupski Address Departments of Molecular and Human Genetics Baylor College of Medicine Houston TX 77030 USA. Current address sabbatical until July 2005 Wellcome Trust Sanger Institute Hinxton Cambridge CB10 1SA UK. E-mail ji2@ Published 28 September 2004 Genome Biology 2004 5 242 The electronic version of this article is the complete one and can be found online at http 2004 5 10 242 2004 BioMed Central Ltd Abstract Homologous recombination between alleles or non-allelic paralogous sequences does not occur uniformly but is concentrated in hotspots with high recombination rates. Recent studies of these hotspots show that they do not share common sequence motifs but they do have other features in common. Homologous recombination is the process whereby two DNA sequence substrates that share a significant stretch of identity are brought together in an enzyme-catalyzed reaction and undergo strand exchange to give a product that is a novel amalgamation of the two substrates. It occurs during meiosis leading to crossovers between alleles allelic homologous recombination AHR and during repair of doublestrand breaks in DNA and other processes leading to recombination between paralogous sequences non-allelic homologous recombination NAHR also known as ectopic recombination . The intermediates of NAHR can be resolved to give several products including deletions duplications and inversion rearrangements or as in the case of AHR the replacement of one sequence by a homologous one gene conversion . When NAHR results in a duplication in one product it is usually accompanied by a reciprocal deletion in the other. Low-copy repeats that can induce NAHR account for 5-10 of the human genome 1 and rearrangements between them can result in a class of diseases known as genomic disorders 2 3 . Finding hotspots It might be thought that homologous .