Demasculinization of X chromosomes in the Drosophila genus
Demasculinization of X chromosomes in the Drosophila genus
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DOI：
10.1038/nature06330
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发表时间：
2007-11-08
期刊：
影响因子：
64.8
通讯作者：
Oliver, Brian
中科院分区：
文献类型：
--
作者：
Sturgill, David;Zhang, Yu;Oliver, Brian
X染色体的进化与常染色体不同，但一般的指导原则还没有出现（1）。例如，具有雄性偏好表达的基因在D的X染色体上代表不足。黑腹按蚊（2），但随机分布在冈比亚按蚊（3）的基因组中。在直接的全球分析实验中，使用物种特异性的微阵列，我们发现了一个几乎相同的缺乏基因与男性偏向表达的D。melanogaster、黑腹果蝇D. simulans、D. yakuba，尖吻隐翅虫D. ananassae，黑腹叶蝉D. virilis和D. mojavensis X染色体。我们在D的neo-X上观察到同样的代表性不足。伪暗已经表明，X染色体的早熟减数分裂沉默解释了线虫（4）、哺乳动物（5）和果蝇（6）中X染色体雄性偏好表达的减少。我们发现，在体细胞和有丝分裂的雄性生殖细胞中，具有男性偏好表达的X染色体基因表达不足。这些数据与简单的X染色体失活模型不相容。使用表达谱分析和比较序列分析，我们表明，选择性基因灭绝的X染色体上，创建新的基因的常染色体和改变基因组位置的现有基因有助于不寻常的X染色体基因内容。
X chromosomes evolve differently from autosomes, but general governing principles have not emerged(1). For example, genes with male-biased expression are under-represented on the X chromosome of D. melanogaster(2), but are randomly distributed in the genome of Anopheles gambiae(3). In direct global profiling experiments using species-specific microarrays, we find a nearly identical paucity of genes with male-biased expression on D. melanogaster, D. simulans, D. yakuba, D. ananassae, D. virilis and D. mojavensis X chromosomes. We observe the same under-representation on the neo-X of D. pseudoobscura. It has been suggested that precocious meiotic silencing of the X chromosome accounts for reduced X chromosome male-biased expression in nematodes(4), mammals(5) and Drosophila(6). We show that X chromosome genes with male-biased expression are under-represented in somatic cells and in mitotic male germ cells. These data are incompatible with simple X chromosome inactivation models. Using expression profiling and comparative sequence analysis, we show that selective gene extinction on the X chromosome, creation of new genes on autosomes and changed genomic location of existing genes contribute to the unusual X chromosome gene content.