The Genetics and Genomics of Sex-Ratio Meiotic Drive in Drosophila Affinis

在包括节肢动物、哺乳动物和植物在内的各种后生动物中都发现了性别比减数分裂的驱动力。驱动力的产生是因为自私的性染色体，通常是X染色体，能够削弱异性染色体。其结果是，携带驱动X染色体的男性几乎都生下了女儿。性别比减数分裂驱动的遗传学一直受到驱动基因与大倒位的关联的阻碍。亲缘果蝇性别比系统还有一个额外的复杂程度：缺乏Y染色体的雄性是有生育能力的。事实上，携带X染色体而不携带Y染色体的男性生育的主要是儿子--如果没有Y染色体，携带X染色体的男性似乎有自杀倾向。我提出了一种策略，利用下一代测序对果蝇的性别比减数分裂驱动进行基因组分析。利用驱动和非驱动X染色体的比较基因组学和男性睾丸中两条染色体的转录转录分析相结合的方法，我希望找出与驱动表型相关的候选基因。随后的分析将有助于识别特定的基因。这种方法是新颖的，因为我将尝试绘制非模式物种倒置内的基因图谱，我开发的方法将有助于在其他系统中进行类似的分析。从我们的分析中获得的生物学见解可能有助于揭示性别比减数分裂驱动和性染色体进化的遗传学，这两者都对生育有影响。

Sex-ratio meiotic drive is found in diverse groups of metazoans including arthropods, mammals and plants. Drive occurs because a selfish sex chromosome, usually the X chromosome, is able to debilitate the opposite sex chromosome. The result is that males carrying the driving X chromosome produce almost all daughters. Understanding the genetics of sex-ratio meiotic drive has been hindered by the association of drive loci with large inversions. The Drosophila affinis sex-ratio system has an additional level o complexity: males lacking a Y chromosome are fertile. In fact, a male with a driving X chromosome and no Y produces mostly sons - the driving X appears to be suicidal in the absence of a Y chromosome. I propose a strategy using next generation sequencing for genomic analysis of sex-ratio meiotic drive in Drosophila affinis. Using a combination of comparative genomics of the driving and non-driving X chromosomes and transcriptomic analysis of both chromosomes in males testes, I hope to identify candidate genes involved in the drive phenotype. Subsequent analysis will help identify specific genes. The approach is novel in that I will be attempting to map genes within inversions in a non-model species, and the methods I develop will facilitate similar analysis in other systems. The biological insight obtaine from our analysis may shed light on the genetics of sex-ratio meiotic drive and sex chromosome evolution, both of which have implications for fertility.