自然选择导致的适应性进化是生物多样性产生的主要动力，然而目前对植物物种形成与适应性分化的遗传基础还知之甚少。本项目拟以差异适应于不同光照环境的野牡丹属（Melastoma）姐妹种毛菍和野牡丹为研究对象，1）采用群体基因组重测序的方法，检测异域和同域分布的野牡丹和毛菍群体基因组分化的式样，区分地理隔离对基因组分化的影响，鉴定高度分化的基因组区域以及受到自然选择作用的位点，结合基因组注释探究受选择作用基因的功能与物种适应性分化的相关性；2）采用ddRAD技术对已经获得的毛菍和野牡丹F2代作图群体进行高密度遗传图谱的构建和重要适应性性状（包括花期、叶片和茎上毛状体等）的QTL定位，解析重要适应性性状的QTL的数目、位置和效应，确定适应性性状的QTL是否位于基因组的高度分化区域。两方面研究结果结合以揭示毛菍和野牡丹适应性分化的遗传基础，理解物种形成过程中的生态背景、进化力量与分子机制。

Adaptive evolution by natural selection is the primary force shaping biological diversity. However, little has been known about the genetic basis of speciation and adaptive divergence in plants. The two sister species of Melastoma, M. sanguineum and M. candidum, are differentially adapted to their own habitats with different light intensity. Here we will use M. sanguineum and M. candidum as a study system, 1) to examine the patterns of interspecific genomic divergence between allopatric and sympatric populations, distinguish the influence of geographic isolation on genomic divergence, identify highly divergent genomic regions and genes under positive selection, and investigate the correlationships between functions of genes under positive selection and adaptive divergence; 2) to construct a high-density genetic map and characterize the number, location and effect of QTLs of important adaptive traits (including flowering time, trichomes in the leaves and stems, etc) based on an F2 mapping population we have already established, and see if QTLs of these adaptive traits are located on the highly divergent genomic regions. Taken together, we aim to reveal the genetic basis of adaptive divergence between M. sanguineum and M. candidum, and understand the ecological settings, evolutionary forces and molecular mechanisms of the speciation process.