Genomic structure and evolution of the ancestral chromosome fusion site in 2ql3-2ql4.1 and paralogous regions on other human chromosomes
Genomic structure and evolution of the ancestral chromosome fusion site in 2ql3-2ql4.1 and paralogous regions on other human chromosomes
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DOI：
10.1101/gr.337602
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发表时间：
2002-11-01
期刊：
影响因子：
7
通讯作者：
Trask, BJ
中科院分区：
文献类型：
--
作者：
Fan, Y;Linardopoulou, E;Trask, BJ
人类的2号染色体是由在其他灵长类动物中保持分离的两条祖先染色体头对头融合而形成的。曾经位于祖先染色体末端附近的序列现在位于2ql3-2ql4.1。这些序列的一部分在融合之前已经复制到其他位置。在这里，我们分析了融合位点周围>600 kb的基因组结构和进化历史，以及其他人类染色体上密切相关的序列。紧挨着标记融合位点的退化端粒重复序列的倒转阵列的序列块在许多位置（主要是亚端粒位置）被复制。此外，168 kb的着丝粒-近端片段的大部分在9pter9pll处复制。2、9q13，平均序列同源性98% ~ 99%。在融合位点的远端有一个67kb的块，与22位的序列高度同源。第三个-100-kb段与第一季度的区域96%相同。通过整合这些同源块的范围和相似性数据，包括系统发育信息重复元素的存在，以及对非人灵长类动物染色体分布的观察，我们推断出导致它们当前排列的重复顺序。其中一些重复的片段可能与灵长类动物进化过程中反转的断点和人类中反复发生的染色体重排有关。
Human chromosome 2 was formed by the head-to-head fusion of two ancestral chromosomes that remained separate in other primates. Sequences that once resided near the ends of the ancestral chromosomes are now interstitially located in 2ql3-2ql4.1. Portions of these sequences had duplicated to other locations prior to the fusion. Here we present analyses of the genomic structure and evolutionary history of >600 kb surrounding the fusion site and closely related sequences on other human chromosomes. Sequence blocks that closely flank the inverted arrays of degenerate telomere repeats marking the fusion site are duplicated at many, primarily subtelomeric, locations. In addition, large portions of a 168-kb centromere-proximal block are duplicated at 9pter, 9pll.2, and 9ql3, with 98%-99% average sequence identity. A 67-kb block oil the distal side of the fusion site is highly homologous to sequences at 22qter. A third -100-kb segment is 96% identical to a region in 2qll.2. By integrating data on the extent and similarity of these paralogous blocks, including the presence of phylogenetically informative repetitive elements, with observations of their chromosomal distribution in nonhuman primates, we infer the order of the duplications that led to their current arrangement. Several of these duplicated blocks may be associated with breakpoints of inversions that occurred during primate evolution and of recurrent chromosome rearrangements in humans.