从多基因互作及miRNA调控网络水平研究生殖隔离的遗传机制

Reproductive isolation is one of the most challenging topics in speciation. Based on conventional genetics methods, it is difficult to precisely detect “speciation gene” location and perform gene replacement, and it is even harder for systematic research in a large scale. In this study, we will apply population genetics theories to survey highly diversified gene regions and perform lots of precise gene replacements using CRISPR/Cas9 in Drosophila, aiming at revealing multiple genes regulation and their function on complex traits; we will conduct adaptive microRNA (miRNA) knock-out, focusing on the effects and contributions of regulatory elements to reproductive isolation; according to population genomics data, we will also find highly diversified miRNA target sites and perform functional test in Drosophila melanogaster sub populations, unraveling the effects of coevolution of miRNA and its binding sites in recent speciation; we will establish mathematical model from food web theory for gene regulatory network, explore how miRNA contribute to system stability, and its biological meaning relevant to speciation. With gene, regulatory elements and gene regulatory network in mind, we will focus on the core issues of speciation, trying to clarify the genetic mechanism of multi-gene regulatory network and the evolution principles for complex traits.

生殖隔离是物种形成研究中最具挑战性的方向之一，其主要研究困难是因为基于传统遗传学方法难以对“物种形成基因”进行精确定位和替换，更难以进行大规模系统性研究。本研究在黑腹果蝇及其近缘种中，通过群体遗传学方法在基因组中筛选高度分化的区域，利用CRISPR/Cas9等新型基因编辑技术，进行大量基因替换，验证多基因对生殖隔离的调控与功能；同时，敲除多个适应性进化miRNA，探究转录后调控因子对生殖隔离的影响与贡献；通过群体基因组数据，寻找黑腹果蝇群体内高分化的靶位点并验证其功能，揭示miRNA及其靶位点的共进化在种系分化中的作用；从基因调控网络出发，利用食物网的理论构建数学模型，探究miRNA对基因调控网络稳定性的作用，并揭示其对生殖隔离形成及演化的意义。本研究基于基因、调控因子、基因调控网络这三个立足点，将围绕生殖隔离这一核心问题，系统阐明多基因调控网络的遗传机制和复杂性状的演化规律。

本研究基于基因、调控因子、基因调控网络这三个立足点，聚焦生殖隔离形成及其过程中演化驱动力的作用规律这一核心科学问题，通过对包括果蝇在内的多个微进化研究体系的开展理论和实证探索，从多个尺度系统阐明了多基因调控网络的遗传机制和复杂性状的演化规律。立项以来，课题组主要开展了以下三个方面研究：1.）研究果蝇 miRNA 的演化历史，揭示适应性进化的 miRNA 对生殖隔离相关性状的影响及其动态演化规律；2）发展基因调控网络稳定性的理论框架，研究 miRNA 对基因调控网络稳定性的影响；3）发展适应性进化理论和实验研究体系，在多基因互作视角下研究物种形成过程中复杂性状的演化机制及各适应性进化驱动力的作用规律。本项目的开展可为探究复杂性状的演化遗传规律提供新的启发。