Transcriptional and genic basis of incipient speciation

描述(由申请人提供)：我们的总体目标是在物种形成的早期阶段了解表型差异的遗传和转录基础。我们将研究黑腹果蝇Z(津巴布韦)和M(世界性)行为种族在交配行为上的差异(Wu等人。1995年；Hollocher等人。1997a，b；Ting et al.2001)。目标1-在基因水平上，我们将在表达基因的全基因组扫描中识别Z和M小种之间高度分化的核苷酸位点。这些种族分化位点将锚定转录和表型分化的遗传图谱。我们将在Z型和M型小种之间构建3号染色体的倍增重组(MR)线，以进行这种定位。目的2-在转录水平上，我们将研究MR系(两性头部和生殖器官)的表达谱，并将这些谱与其潜在的基因类型相关联。转录调控是连接表型和基因的重要环节。目的3-在表型水平上，我们将首先尝试使用MR系来寻找表型差异(行为隔离)的转录基础。我们还将把表型差异与基因变化直接联系起来。我们希望确定一些候选的物种形成基因，*并将进行精确的基因替换(Rong和Golic 2000；Greenberg等人，2003)，以证实它们对交配行为的影响。

DESCRIPTION (provided by applicant): Our general goal is to understand the genetic and transcriptional bases of phenotypic divergence at an early stage of speciation. We shall study the divergence in mating behaviors between the Z (for Zimbabwe) and M (cosmopolitan) behavioral races of Orosophila melanogaster (Wu et al. 1995; Hollocher et al. 1997a, b; Ting et al. 2001). Aim 1 - At the genotypic level, we will identify nucleotide sites that are strongly differentiated between the Z and M races in a whole-genome scan of expressed genes. These race-differentiating sites will anchor genetic mapping of transcription and phenotypic divergence. We will construct multiply recombined (MR) lines for Chromosome 3 between the Z- and M-races for such mapping. Aim 2 - At the transcriptional level, we shall study the expression profiles of the MR lines (in heads and reproductive organs of the 2 sexes) and correlate these profiles with their underlying genotypes. The regulation of transcription is important in linking phenotype and genotype. Aim 3 - At the phenotypic level, we shall first attempt to find the transcriptional basis of the phenotypic divergence (behavioral isolation), using the MR lines. We shall also link phenotypic divergence to genotypic changes directly. We expect to identify a number of candidate "speciation genes,* and will carry out precise gene replacement (Rong and Golic 2000; Greenberg et al. 2003) to confirm their effects on the mating behavior.