NONMETHYLATED ISLANDS IN FISH GENOMES ARE GC-POOR
NONMETHYLATED ISLANDS IN FISH GENOMES ARE GC-POOR
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DOI：
10.1093/nar/19.7.1469
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发表时间：
1991-04-11
影响因子：
14.9
通讯作者：
BIRD, A
中科院分区：
文献类型：
--
作者：
CROSS, S;KOVARIK, P;BIRD, A
在迄今为止研究的脊椎动物基因组中，许多基因的5'端与称为CpG岛的独特序列相关。 CpG岛具有三个特性：它们是非甲基化的;二核苷酸CpG以碱基组成预测的频率出现;并且它们富含GC。 出乎意料的是，我们发现某些鱼类中的CpG岛仅具有前两种性质;即，与大量基因组DNA相比，它们的GC含量没有升高。 基于这一发现，我们推测，GC丰富的CpG岛在脊椎动物以外的鱼类是一个被动的结果，在开放的染色质区域的核苷酸前体池的条件下，有偏见的突变率较高。
In the vertebrate genomes studied to date the 5' end of many genes are associated with distinctive sequences known as CpG islands. CpG islands have three properties: they are non-methylated; the dinucleotide CpG occurs at the frequency predicted by base composition; and they are GC-rich. Unexpectedly we have found that CpG islands in certain fish only have the first two properties; that is, their GC-content is not elevated compared to bulk genomic DNA. Based on this finding, we speculate that the GC-richness of CpG islands in vertebrates other than fish is a passive consequence of a higher mutation rate in regions of open chromatin under conditions where the nucleotide precursor pools are biased.