Duplication, coclustering, and selection of human Alu retrotransposons
Duplication, coclustering, and selection of human Alu retrotransposons
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DOI：
10.1073/pnas.0308084100
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发表时间：
2004-02-03
影响因子：
11.1
通讯作者：
Jurka, MV
中科院分区：
文献类型：
--
作者：
Jurka, J;Kohany, O;Jurka, MV
Alu和L1是非反转录转座子家族，约占人类基因组的30%。年轻的Alu和L1元素的基因组分布是非常相似的，但随着时间的推移，富含GC的DNA中的Alu密度增加相比，L1密度。在这里，我们分析了可能导致这种现象的两个过程。首先，人类基因组中的DNA复制更频繁地发生在富含Alu和GC的染色体区域，而不是富含AT的染色体区域。第二，大多数Alu元素倾向于彼此共聚，但最近的逆位元素很可能被插入到现有的集群之外。这些“独立”的元素似乎很快从基因组中消失。我们还报告说，随着时间的推移，最近逆转的Alu家族的Y染色体上的密度迅速下降，而Alu的X染色体上的密度增加相对于常染色体的密度。我们建议，这些变化的染色体比例的Alu密度和消除独立的Alu代表了相同的过程中的父Alu选择。我们还建议，长期的铝积累在GC丰富的DNA与DNA复制启动铝集群中的重组活性升高。
Alu and L1 are families of non-retrotransposons representing approximate to30% of the human genome. Genomic distributions of young Alu and L1 elements are quite similar, but over time, Alu densities in GC-rich DNA increase in comparison with L1 densities. Here we analyze two processes that may contribute to this phenomenon. First, DNA duplications in the human genome occur more frequently in Alu- and GC-rich than in AT-rich chromosomal regions. Second, most Alu elements tend to be coclustered with each other, but recently retroposed elements are likely to be inserted outside the existing clusters. These "stand-alone" elements appear to be rapidly eliminated from the genome. We also report that over time, the densities of recently retroposed Alu families on chromosome Y decline rapidly, whereas Alu densities on chromosome X increase relative to autosomal densities. We propose that these changes in the chromosomal proportions of Alu densities and the elimination of stand-alone Alus represent the same process of paternal Alu selection. We also propose that long-term Alu accumulation in GC-rich DNA is associated with DNA duplication initiated by elevated recombinogenic activities in Alu clusters.