黄胸鼠和褐家鼠种间互作对信息素性状位移的可能影响及调控机制

The sexual signals between closely related species are highly similar, however, when they are sympatric, the divergences between the signals are enforced for right mate choice. Only a study case of sex pheromone character diaplacement has been recently reported in butterflies. Such studies have been never attempted in rodents that mainly rely on pheromonal communication in most behavioral contexts. The populations of brown rats in north China have been allopatric for a long time, however, in the last 30 years, their closely related species, Asian house rats, showed a striking northward rang expasion. Therefore, using the invasion process, we plan to explore the sympatric effects of the rats on sex pheromone character displacement and the underlying mechanisms， including (1) the sources and genetic diversity of invasive Asian house rats ; (2) comparision of the genetic diversity of rown rat populations across sympatric and allopatric areas;(3) how behavioral interactions, olfactory recognition and sex pheromone components to be affected by coexistence and competition of these two rats species and the underlying physiological mehcanisms (immediate cause); (4) Effects of chemical communication-based mate preferences on the divergences of sex and species pheromones and their genetic basis. Four to six papers in English are expected to be published , and 4-6 postgratitutes and postdoctors will be trained with the supports from the grant.

近缘种间的性信号很相似，同域分布时性信号分化增强, 使配偶识别准确。过去针对性信息素的生殖性状位移的研究仅蝶类一例报道。鼠类主要依靠信息素通讯。北方褐家鼠种群长期缺乏近缘种竞争，但是最近30年，其近缘种黄胸鼠显著向北方扩展。我们利用黄胸鼠的生态入侵这个现象， 探索黄胸鼠和褐家鼠同域分布对信息素性状位移的影响，具体包括（1）北扩黄胸鼠种群的来源或路径及种群遗传多样性的变化；（2）褐家鼠在与黄胸鼠古老同域分布区、新的分布区和异域分布区遗传多样性变化；(3) 种间的行为互作、嗅觉识别、信息素组成与两个近缘鼠种的共存和竞争的关系及生理基础（近因）；(4) 化学通讯调节的黄胸鼠和褐家鼠的配偶选择对种间信息素分化的影响和可能的遗传基础。旨在阐明黄胸鼠和褐家鼠的竞争与性信息素分化和种间行为生殖隔离形成的过程及进化特点。本项目拟发表4-6篇英文论文，培养4-6名研究生和博士后。

近缘种间的性信号很相似，同域分布时性信号分化增强, 使配偶识别准确。鼠类主要依靠信息素通讯。北方褐家鼠种群长期缺乏近缘种竞争，但是最近30年，其近缘种黄胸鼠显著向北方扩展。我们发现褐家鼠尿液信息素含量非常丰富，超声没有性别差异，而黄胸鼠的尿液信息素含量非常稀少，不存在性别差异，而超声产生了性别差异，说明同域近缘种的性选择信号截然不同；经过黄胸鼠和褐家鼠种间气味等的长期刺激之后，雄性黄胸鼠自身的气味的性吸引力增强，雄性褐家鼠自身气味的性吸引力减弱，说明种间的长期互作可能会促进黄胸鼠繁殖成功，而降低褐家鼠繁殖成功，有利于黄胸鼠种群替代褐家鼠种群；对采自全国范围内（包括北扩群体和南方源群体）的35个黄胸鼠（Rattus tanezumi）进行了全基因组重测序，利用所有的SNPs进行种群遗传结构和进化分析表明，北扩的黄胸鼠可分为华北和西北两个群体。其中与华北黄胸鼠进化关系最近的是湖北个体；而与西北关系最近的是湖南个体，免疫系统和嗅觉系统发生快速遗传分化；遗传多样性分析表明西藏群体和北扩的西北群体的有效群体大小均小于南方群体，而北扩的华北群体则与南方群体相差不大，华北群体可能有多个入侵来源，且与其他群体有较强的基因流；发现了7个在该物种中固定下来的与感染和免疫有关的无义突变，8个与抗凝血剂抗性相关的错义突变，这可能与该物种对携带病原的抗性及对广泛使用的灭鼠药的抗性等生态适应性有关。褐家鼠在新疆近期入侵过程中，信号接收与传导、免疫以及肾脏发育三个方面发生正选择基因显著富集。本项目已经发表6篇英文论文，培养4名研究生和博士后。