The evolutionary origin of a complex scrambled gene
The evolutionary origin of a complex scrambled gene
复制标题
DOI：
10.1073/pnas.0507682102
复制
发表时间：
2005-10-18
影响因子：
11.1
通讯作者：
Landweber, LF
中科院分区：
文献类型：
--
作者：
Chang, WJ;Bryson, PD;Landweber, LF
某些种类的纤毛虫通过大量的DNA消除和基因组重排，在体细胞核中构建基因大小的“染色体”。一个例子是广泛混乱的DNA聚合酶，一个被分成48个片段的基因，分布在柱甲的两个不连锁的位点上。为了理解这种复杂现象在进化过程中的出现，我们研究了DNA聚合酶α基因在几个早期的分歧物种，代表进化中间体。将这些数据映射到进化树上表明，该基因在进化过程中通过一系列步骤变得广泛碎片化和混乱，每个步骤都导致更大的复杂性。我们的研究结果还表明，在体细胞核发育过程中，内含子序列作为DNA的缺失可能是内含子丢失的机制。
Some species of ciliates undergo massive DNA elimination and genome rearrangement to construct gene-sized "chromosomes" in their somatic nucleus. An example is the extensively scrambled DNA polymerase a gene that is broken into 48 pieces and distributed over two unlinked loci in Stylonychia. To understand the emergence of this complex phenomenon during evolution, we examined DNA polymerase alpha genes in several earlier diverging species, representing evolutionary intermediates. Mapping these data onto an evolutionary tree suggests that this gene became extensively fragmented and scrambled over evolutionary time through a series of steps, each leading to greater complexity. Our results also suggest a possible mechanism for intron loss by deletion of intron sequences as DNA during development of the somatic nucleus.