Chromatin diminution leads to rapid evolutionary changes in the organization of the germ line genomes of the parasitic nematodes A. suum and P. univalens
Chromatin diminution leads to rapid evolutionary changes in the organization of the germ line genomes of the parasitic nematodes A. suum and P. univalens
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DOI：
10.1016/j.molbiopara.2003.11.001
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发表时间：
2004-03-01
影响因子：
1.5
通讯作者：
Müller, F
中科院分区：
文献类型：
--
作者：
Bachmann-Waldmann, C;Jentsch, S;Müller, F
寄生线虫猪蛔虫（Ascaris suum）和单价副蛔虫（Parascaris univalens）的染色质减少是一个相当复杂的分子现象，包括染色体断裂、DNA降解和新端粒的形成。在给定的消除位点，DNA断裂和新的端粒添加不是发生在单个染色体基因座，而是发生在几个端粒长的染色体区域内的许多不同位置，称为染色体断裂区域（CBR）。在这里，我们描述的克隆和表征的7个CBR从A。suum和P.univalens，我们表明这一过程在两个物种之间是保守的。详细的序列比较提供的证据表明，CBR及其侧翼区的序列对于消除位点的指定并不直接重要。7个CBR中有6个在两种线虫之间是保守的，这表明它们已经存在于共同的祖先中。我们提出了一个假设，即消除过程确保了功能性体细胞基因组的维持，同时允许生殖系基因组发生极其迅速和深刻的变化，从而允许开发新的生殖系特异性功能，从而在进一步进化过程中为染色质消除线虫提供选择性优势。(C)2003 Elsevier B.V.保留所有权利。
Chromatin diminution in the parasitic nematodes Ascaris suum and Parascaris univalens represents a rather complex molecular phenomenon that includes chromosomal breakage, DNA degradation and new telomere formation. At a given elimination site, DNA breakage and new telomere addition does not take place at a single chromosomal locus but at many different places within a several kilobase long chromosomal region, referred to as chromosomal breakage region (CBR). Here we describe the cloning and the characterisation of seven CBRs from A. suum and P. univalens and we show that the process has been conserved between the two species. A detailed sequence comparison provides evidence that the sequences of the CBRs and their flanking regions are not directly important for the specification of the elimination sites. Six out of the seven CBRs are conserved between the two nematode species, suggesting that they have already existed in a common ancestor. We present a hypothesis stating that the elimination process ensures the maintenance of a functional somatic genome and concomitantly allows extremely rapid and profound changes in the germ line genome, thereby allowing the development of new germ line specific functions and thus providing a selective advantage for the chromatin eliminating nematodes during further evolution. (C) 2003 Elsevier B.V. All rights reserved.