New Insights into Centromere Organization and Evolution from the White-Cheeked Gibbon and Marmoset
New Insights into Centromere Organization and Evolution from the White-Cheeked Gibbon and Marmoset
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DOI：
10.1093/molbev/msp101
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发表时间：
2009-08-01
影响因子：
10.7
通讯作者：
Ventura，M.
中科院分区：
文献类型：
--
作者：
Cellamare，A.;Catacchio，C. R.;Ventura，M.
α-卫星DNA是灵长类着丝粒的主要组成部分，与大多数基因组序列相比，其序列组装困难，进化速度快，其进化历史难以确定。通过使用几种方法，我们已经克隆，测序，并表征了两个物种的α-卫星序列，代表灵长类动物生殖的关键节点：白颊长臂猿，一个较小的猿，和绒猴，新世界的猴子。序列分析表明，白颊猕猴和绒猴的α-卫星序列分别由约171 bp和约342 bp组成，它们都缺乏人类和类人猿的高级结构。荧光原位杂交结果表明，白颊相思鸟基因组中α-卫星分布广泛，包括着丝粒、端粒和染色体间质定位。另一方面，绒猴的着丝粒呈现高度分化的二聚体结构，其长度约为342 bp，单体间的相似性远低于以往报道的二聚体，代表了一种古老的二聚体结构，这些数据为灵长类动物着丝粒序列的进化提供了线索。我们的研究结果表明，不同灵长类物种之间α-卫星DNA的结构，组织和进化存在根本差异，支持以下观点：1）灵长类动物中所有的着丝粒序列都是通过基因组扩增，不等交换和序列均化而进化的，使用171 bp单体作为基本播种单位; 2）着丝粒功能与相对较短的重复元件有关，此外，我们的数据表明，复杂的高阶重复结构是原始人类谱系的一个特点，显示了人类更复杂的组织。
The evolutionary history ofα-satellite DNA, the major component of primate centromeres, is hardly defined because of the difficulty in its sequence assembly and its rapid evolution when compared with most genomic sequences. By using several approaches, we have cloned, sequenced, and characterizedα-satellite sequences from two species representing critical nodes in the primate phylogeny: the white-cheeked gibbon, a lesser ape, and marmoset, a New World monkey. Sequence analyses demonstrate that white-cheeked gibbon and marmosetα-satellite sequences are formed by units of ∼171 and ∼342 bp, respectively, and they both lack the high-order structure found in humans and great apes. Fluorescent in situ hybridization characterization shows a broad dispersal ofα-satellite in the white-cheeked gibbon genome including centromeric, telomeric, and chromosomal interstitial localizations. On the other hand, centromeres in marmoset appear organized in highly divergent dimers roughly of 342 bp that show a similarity between monomers much lower than previously reported dimers, thus representing an ancient dimeric structure.All these data shed light on the evolution of the centromeric sequences in Primates. Our results suggest radical differences in the structure, organization, and evolution ofα-satellite DNA among different primate species, supporting the notion that 1) all the centromeric sequence in Primates evolved by genomic amplification, unequal crossover, and sequence homogenization using a 171 bp monomer as the basic seeding unit and 2) centromeric function is linked to relatively short repeated elements, more than higher-order structure.Moreover, our data indicate that complex higher-order repeat structures are a peculiarity of the hominid lineage, showing the more complex organization in humans.