tailieunhanh - Báo cáo y học: "Comparative genomics reveals birth and death of fragile regions in mammalian evolutio"

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: Comparative genomics reveals birth and death of fragile regions in mammalian evolution. | Alekseyev and Pevzner Genome Biology 2010 11 R117 http 2010 11 11 R117 Genome Biology RESEARCH Open Access Comparative genomics reveals birth and death of fragile regions in mammalian evolution Max A Alekseyev1 Pavel A Pevzner2 Abstract Background An important question in genome evolution is whether there exist fragile regions rearrangement hotspots where chromosomal rearrangements are happening over and over again. Although nearly all recent studies supported the existence of fragile regions in mammalian genomes the most comprehensive phylogenomic study of mammals raised some doubts about their existence. Results Here we demonstrate that fragile regions are subject to a birth and death process implying that fragility has a limited evolutionary lifespan. Conclusions This finding implies that fragile regions migrate to different locations in different mammals explaining why there exist only a few chromosomal breakpoints shared between different lineages. The birth and death of fragile regions as a phenomenon reinforces the hypothesis that rearrangements are promoted by matching segmental duplications and suggests putative locations of the currently active fragile regions in the human genome. Background In 1970 Susumu Ohno 1 came up with the Random Breakage Model RBM of chromosome evolution implying that there are no rearrangement hotspots in mammalian genomes. In 1984 Nadeau and Taylor 2 laid the statistical foundations of RBM and demonstrated that it was consistent with the human and mouse chromosomal architectures. In the next two decades numerous studies with progressively increasing resolution made RBM the de facto theory of chromosome evolution. RBM was refuted by Pevzner and Tesler 3 who suggested the Fragile Breakage Model FBM postulating that mammalian genomes are mosaics of fragile and solid regions. In contrast to RBM FBM postulates that rearrangements are mainly happening in fragile regions forming only a small portion of the mammalian .

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