Prigent Stéphane R, Matsubayashi Hiroshi, Yamamoto Masa-Toshi
Drosophila Genetic Resource Center, Kyoto Institute of Technology, Kyoto 616-8354, Japan.
Genes Genet Syst. 2009 Oct;84(5):353-60. doi: 10.1266/ggs.84.353.
Speciation genes are responsible for genetic incompatibilities in hybrids of incipient species and therefore participate in reproductive isolation leading to complete speciation. Hybrid males between Drosophila melanogaster females and D. simulans males die at late larval or prepupal stages due to a failure in chromosome condensation during mitosis. However a mutant male of D. simulans, named Lethal hybrid rescue (Lhr), produces viable hybrid males when crossed to females of D. melanogaster. Recently the Lhr gene has been proposed as corresponding to the CG18468 gene in D. melanogaster. However this identification relied on sequence characteristics more than on a precise mapping and the use of the GAL4/UAS system to drive the transgene in D. melanogaster might have increased the complexity of interaction. Thus here we propose an independent identification of the Lhr gene based on a more precise mapping and transgenic experiments in D. simulans. We have mapped the Lhr gene by using Single Nucleotide Polymorphisms (SNPs) and identified within the candidate region the gene homologous to CG18468 as the Lhr gene as it was previously reported. Transgenic experiments in D. simulans with the native promoter of CG18468 prove that it is the Lhr gene of D. simulans by inducing the lethality of the hybrid males.
物种形成基因导致初始物种杂种出现遗传不相容性，因此参与生殖隔离，最终导致完全物种形成。黑腹果蝇雌性与拟果蝇雄性杂交产生的杂种雄性在幼虫后期或蛹前期死亡，原因是有丝分裂期间染色体浓缩失败。然而，拟果蝇的一个名为致死杂种拯救（Lhr）的突变雄性与黑腹果蝇雌性交配时能产生可存活的杂种雄性。最近，有人提出Lhr基因对应于黑腹果蝇中的CG18468基因。然而，这种鉴定更多地依赖于序列特征，而非精确的定位，并且在黑腹果蝇中使用GAL4/UAS系统驱动转基因可能增加了相互作用的复杂性。因此，我们在此基于更精确的定位和在拟果蝇中的转基因实验，提出对Lhr基因进行独立鉴定。我们利用单核苷酸多态性（SNP）对Lhr基因进行了定位，并在候选区域内确定了与CG18468同源的基因就是Lhr基因，正如之前所报道的那样。在拟果蝇中使用CG18468的天然启动子进行转基因实验，通过诱导杂种雄性的致死性，证明它就是拟果蝇的Lhr基因。
