Microsatellite accumulation on the Y chromosome in Silene latifolia
Microsatellite accumulation on the Y chromosome in Silene latifolia
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DOI：
10.1139/g08-024
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发表时间：
2008-05-01
期刊：
影响因子：
3.1
通讯作者：
Kejnovsky, Eduard
中科院分区：
文献类型：
--
作者：
Kubat, Zdenek;Hobza, Roman;Kejnovsky, Eduard
雌雄异株植物宽叶硅烯具有进化年轻的性染色体，因此可以作为研究性染色体进化早期阶段的模式系统。性染色体在结构和进化模式上往往与常染色体截然不同。宽叶黄花的Y染色体特别独特，因为它的大小与较小、退化的哺乳动物Y染色体的大小形成了鲜明对比。人们认为，宽叶狼尾草Y染色体上重组的抑制可能导致了重复序列的积累，这是其大小的原因。在这里，我们使用荧光原位杂交技术(FISH)研究了宽叶牡丹中各种微卫星的染色体分布，包括所有可能的单核苷酸、双核苷酸和三核苷酸。我们的结果表明，大多数微卫星积累在Y染色体的Q臂上，与P臂相比，Y染色体的Q臂最近停止重组，积累重复DNA序列的时间较少。根据这些结果，我们可以推测微卫星在基因组扩张之前的区域已经积累，支持重复DNA序列的积累发生在基因退化之前的观点，而不是因为基因退化。
The dioecious plant Silene latifolia possesses evolutionarily young sex chromosomes, and so serves as a model system to study the early stages of sex chromosome evolution. Sex chromosomes often differ distinctly from autosomes in both their structure and their patterns of evolution. The S. latifolia Y chromosome is particularly unique owing to its large size, which contrasts with the size of smaller, degenerate mammalian Y chromosomes. It is thought that the suppression of recombination on the S. latifolia Y chromosome could have resulted in the accumulation of repetitive sequences that account for its large size. Here we used fluorescence in situ hybridization (FISH) to study the chromosomal distribution of various microsatellites in S. latifolia including all possible mono-, di, and tri-nucleotides. Our results demonstrate that a majority of microsatellites are accumulated on the q arm of the Y chromosome, which stopped recombining relatively recently and has had less time to accumulate repetitive DNA sequences compared with the p arm. Based on these results we can speculate that microsatellites have accumulated in regions that predate the genome expansion, supporting the view that the accumulation of repetitive DNA sequences occurred prior to, not because of, the degeneration of genes.