遗传变异是物种演化的动力之一。现今对基因功能的知识大多基於对模式生物的研究，有鉴于大数据时代来临，比较生物学已成为研究的重要方向。十字花科包含许多重要的作物，在科研上更有良好优势，不但包含分子生物及生理学的模式物种，并有大量的基因组数据，非常适合作为模式植物科。系统进化关系则是作为许多研究领域的骨架，能使比较生物学发挥最大的效益。然而，十字花科的系统进化关系较为复杂，先前研究中用于建构系统进化关系的序列的信息量高度不足，因此许多关系仍未定。当前测序方法的进展则提供了一个良好的契机解决此问题。因此，本项目旨在高完整度的收集物种，测定大量数据，利用核基因重建出清晰、完整的系统发育关系。同时将重建十字花科演化历史，包括分化年份与速率，型态演化、古地理气候变化等，并分析花、果实及抗逆相关基因家族的演化历史与各支系中的特异性。申请人与国外的十字花科专门学者有良好的合作互动，对于项目进展将有高度帮助。

Evolution of new life forms requires initial genetic variation and subsequent natural selection or fixation. To understand gene functions, numerous studies relied heavily on studies of model organisms, such as the model plant Arabidopsis thaliana (L.) Heynh since 1940s. Nowadays, increasing efforts have been made on the comparison of different species. It is particularly important to investigate whether gene functions uncovered in a model organism are conserved among a wider group of species. Comparative studies can provide insights into the conservation and divergence of morphological and physiological characteristics. Also, systematic comparisons of genes, proteins and their interactions between different organisms are beginning to yield insights into the molecular basis of diversity. ..Brassicaceae is an attractive candidate as an evolutionary model family in many ways. First, Brassicaceae is one of the most well-known and diverse plant families, with ∼3700 species and many important agricultural and horticultural members. The family is distributed worldwide, with numerous members being relatively easy to access in temperate regions of the Northern Hemisphere. Secondly, much of the current knowledge of gene functions in developmental and physiological processes of flowering plants comes from studies using the model plant Arabidopsis thaliana. Additional functional studies have been carried out with related crops such as Brassica species. A group of plants with a wide range of evolutionary, ecological, morphological and physiological properties would be an excellent system for such comparative studies. In conclusion, members of the Brassicaceae not only include model system(s) to provide a foundation for understanding gene functions, but also contain crop plants to facilitate the application of the generated new insights in agriculture. The evolutionary history, ecological, morphological and genetic diversity and abundant resources and knowledge of Brassicaceae make it an excellent model family for evolutionary studies...For this purpose, it will be very helpful to understand the evolutionary history of Brassicaceae; however, Brassicaceae phylogeny was poorly resolved in previous studies possibly due to limiting markers used in the reconstructions. In this project, we aim to provide a well-resolved family-wide phylogeny and the associating events during its evolutionary history. We will collect representatives of all tribes, and generate transcriptome datasets for the use of low-copy nuclear orthologous genes as phylogenetic markers. A resolved phylogeny, as well as the results of divergence time and diversification rate estimations and ancestral character reconstructions will be made during this project. Taking the advantage of large datasets here, we will also investigate the evolution of gene families that associate with flower/fruit development and stress tolerance to provide information in understanding the underlying mechanisms among different major clades.