Molecular evolution of MADS genes, and origin and evolution of flowers

被子植物的特征是花由萼片、花瓣、雄蕊和雌蕊组成。花的形态在被子植物的几个谱系中是多样化的。本研究的目的是阐明花的起源及其演化。为此，本研究对在花器官发生中起重要作用的MADS-box基因家族进行了克隆和分析，从被子植物中选择了厚朴、鱼腥草、毛花属、银莲花和铁线莲属作为材料，从裸子植物中选择了银杏。利用RT-PCR方法，分别克隆了15、12、14、10、13、5个MADS-box基因克隆。确定了这些克隆的DNA序列，并与其他已知的MADS-box基因构建了系统发育树。该树表明，来自相同植物的克隆并不构成一个单系支系，而是来自不同植物的序列聚在一起。在某些基因群中，从裸子植物到被子植物的进化提示了基因复制的发生。

Angiosperms is characteristic by having a flower which consists of sepals, petals, stamens and gynoecium. The merphology of flower is diversified in several lineages of angiosperms. The purpose of present study is clarified the origin of flower and its evolution. For this purpose, I have performed a cloning and analysis of MADS-box gene family which is very important in organogenesis of flower.From angiosperms, Magnolia, Houttuynia, Ranunculus, Anemone, and Clematis were selected as materials, and Ginkgo from gymnosperms. As a result using RT-PCR method, 15,12,14,10,13,5 clones of MADS-box genes are cloned from these plants respectively. These clones are determined their DNA sequences and I constructed phylogenetic tree of these genes together with the other known MADS-box genes. The tree indicated that the clones from the same plants do not make a monophyletic clade, but the sequences from the different plants clustered together. And in some gene group, the occurrence of gene duplication is suggested in the way of evolution from gymnosperms to angiosperms.