莴苣属Lactuca L.隶属于菊科菊苣族莴苣亚族，该属植物性状变异较大且与其近缘属植物性状交叉严重，是菊科植物系统发育研究中的难点之一。之前莴苣属的研究仅局限于生菜基因库和少数物种中，缺乏系统性研究。基于二代测序技术的系统基因组学是近年来揭示植物类群不同等级间系统发育关系的重要手段之一。本研究拟以莴苣属物种及其近缘属代表物种（外类群）为研究对象，使用二代测序技术对莴苣属及外类群植物进行高通量测序。通过叶绿体全基因组序列、细胞核保守同源基因序列和核糖体DNA间隔序列来构建莴苣属植物分子系统发育树，结合莴苣属重要的形态学、染色体数目及地理分布等特征，探究莴苣属的界限划分，属内系统发育关系和起源等问题。研究结果也将为莴苣亚族的系统发育以及生菜新种质资源的研究提供一定的理论依据。

Lactuca L. belongs to the subtribe Lactucinae, tribe Cichorieae of the family Asteraceae. The genus has been the difficult and controversial part in the phylogenetic studies of Asteraceae family for a long time, due to the complex and diverse morphological characters within the genus and the resemble features to the species from related genera. Former studies of Lactuca have been focused on the lettuce gene pool and a small amount of species, lacking a systematic study. In recent years, phylogenomics, based on Next Generation Sequencing (NGS) technologies, becomes one of the important tools to investigate the phylogenetic relationships at different levels of plant taxa. This project aims to study the phylogenomics within Lactuca and between Lactuca and representing species from related genera (as outgroups), using high throughput DNA sequencing. The chloroplast genome sequences, nuclear Conserved Ortholog Set (COS) loci and ribosomal intergenic spacer (ITS) will be assembled, annotated and used for constructing phylogenetic trees. Finally, the phylogenetic trees will be combined with some important morphological characters, as well as chromosome number and geographical distribution, to investigate their patterns on the evolutionary trees. The results of this study will contribute to the circumscription of Lactuca, its subgeneric classification and the origin of Lactuca. In the meantime, the results will also shed a new light on the phylogenetic relationships in Lactucinae, as well as new genetic resources for lettuce breeding.