Analysis of intrachromosomal duplications in yeast Saccharomyces cerevisiae:: A possible model for their origin
Analysis of intrachromosomal duplications in yeast Saccharomyces cerevisiae:: A possible model for their origin
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DOI：
10.1093/oxfordjournals.molbev.a026410
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发表时间：
2000-08-01
影响因子：
10.7
通讯作者：
Netter, P
中科院分区：
文献类型：
--
作者：
Achaz, G;Coissac, E;Netter, P
研究了酿酒酵母全基因组在核苷酸序列水平上的染色体内复制。通过寻找每条染色体上存在的长近似重复序列（从30到3，885 bp）进行分析。我们发现，正向和反向重复序列表现出非常不同的特点：两个副本的正向重复序列是更相似的和更长的反向重复序列。此外，与反向重复序列相反，大部分直接重复序列似乎是紧密间隔的。两个拷贝之间的距离（delta）通常小于1 kb。对这些“紧密直接重复序列”的进一步分析显示，δ与两个拷贝之间的同一性百分比之间呈负相关，δ与重复序列长度之间呈正相关。此外，与其他类型的重复序列相反，近端直接重复序列大多位于编码序列（CDS）内。为了解释这些观察结果，我们提出了两个假设：第一，缺失/转换率与δ负相关;第二，存在一种活跃的复制机制，该机制通过这些“初级重复”的染色体重排不断产生紧密的直接重复，其他染色体内重复是结果。"
The complete genome of the yeast Saccharomyces cerevisiae was investigated for intrachromosomal duplications at the level of nucleotide sequences. The analysis was performed by looking for long approximate repeats (from 30 to 3,885 bp) present on each of the chromosomes. We show that direct and inverted repeats exhibit very different characteristics: the two copies of direct repeats are more similar and longer than those of inverted repeats. Furthermore, contrary to the inverted repeats, a large majority of direct repeats appear to be closely spaced. The distance (delta) between the two copies is generally smaller than 1 kb. Further analysis of these "close direct repeats" shows a negative correlation between delta and the percentage of identity between the two copies, and a positive correlation between delta and repeat length. Moreover, contrary to the other categories of repeats, close direct repeats are mostly located within coding sequences (CDSs). We propose two hypotheses in order to interpret these observations: first, the deletion/conversion rate is negatively correlated with delta; second, there exists an active duplication mechanism which continuously creates close direct repeats, the other intrachromosomal repeats being the result, by chromosomal rearrangements of these "primary repeats."