Sex chromosomes and relocation of genes by duplication

描述（由申请人提供）：异形性染色体决定许多物种的雄性和雌性，其研究具有普遍意义。了解性染色体在基因和功能产生上的偏差对于解释性二型性和性染色体进化具有重要意义。发现性染色体从一对常染色体中分化出来;大多数Y染色体退化，X染色体产生剂量补偿。在性染色体复制中，观察到两种主要类型的偏倚（在人类、小鼠和D。黑腹果蝇）：新的基因被Y染色体招募，而重复的基因则逃脱了X染色体。特别是，逆转录显示了复制的方向性，并帮助我们揭示了逃离X染色体的复制品。这些新的重复基因中有许多具有男性特异性功能。因此，它们的位置和表达模式的偏差表明，当这些基因在群体中固定下来，并且获得性别特异性启动子时，就会发生显著的正选择。本项目提出两个目标：[1]研究选择在D.黑腹果蝇，和[2]研究如何收购的男性特异性启动子区域发生在这些新搬迁的逆转录基因在果蝇。利用核苷酸水平的多态性和差异性数据、mRNA表达信息、P元件转化技术、同源重组、直接诱变以及最新的生物信息学工具和分子进化软件来实现这两个目标。

DESCRIPTION (provided by applicant): Heteromorphic sex chromosomes determine males and females in many species and their study is of general interest. Understanding the biases in the generation of genes and functions with respect to sex chromosomes is of primary significance to explaining sexual dimorphism and sex chromosome evolution. The sex chromosomes are found to differentiate from a pair of autosomes; most of the Y chromosome degenerates, and the X chromosome develops dosage compensation. Two main types of biases in the generation of duplicates in relation to sex chromosomes have been observed (in human, mouse and D. melanogaster): new genes are recruited by the Y chromosome and duplicates escape the X chromosome. In particular, retroposition has revealed the directionality of the duplication and has helped us to reveal duplicates that escape the X chromosome. Many of these new duplicate genes have male specific function. So the bias in their location and expression pattern reveals that significant positive selection takes place when those genes become fixed in the population and when they acquire a gender specific promoter. This project proposes two objectives: [1] to study the function and role of selection in retrogenes newly relocated from X to autosome in D. melanogaster, and [2] to study how the acquisition of male specific promoter regions takes place in these newly relocated retrogenes in Drosophila. Data of polymorphism and divergence at the nucleotide level, mRNA expression information, P element transformation technology, homologous recombination, direct mutagenesis and the most up to date bioinformatics tools and molecular evolution software will be exploited to achieve these two objectives.