Study of Origin and Evolution of Ovules

为了阐明花的起源和进化，有必要阐明控制花发育的基因的表达网络。本研究以裸子植物特别是银杏（Ginkgo biloba）的生殖器官为研究对象，采用RT-PCR方法从银杏（Ginkgo biloba）幼胚珠中克隆了MADS基因。我们得到了10个不同的cDNA克隆。对所有已知的MADS基因进行系统发育分析，将其分为8类。其中3个克隆包含ABC模型中已知的B功能基因AP 3/PI组，我们利用RT-PCR和原位杂交技术分析了AP 3/PI组3个基因的表达模式。其中一个在雄性和雌性生殖器官中都有表达。而其余两个基因只在一个生殖器官中表达，即在卵巢中表达。例如，GbMADS 9仅在雄性生殖器官中表达，GbMADS 10仅在雌性生殖器官中表达。

For elucidating origin and evolution of flower, it is necessary to clarify the expression network of genes which control a floral development, In this study, we focused on reproductive organs of Gymnosperms, especially Ginkgo biloba.We cloned MADS genes from young ovules of Ginkgo biloba using RT-PCR method. We have got 10 different cDNA clones. As a result of phylognetic analysis including all known MADS genes from plants, these genes have been classified into 8 groups. Among them 3 clones were included AP3/PI group which have been known as a B-function genes in ABC model.We analyzed expression pattern of the three genes belonging to AP3/PI group, using RT-PCR and in situ hybridization. One of them were expressed both in male and female reproductive organs. However, the rest of two genes were expressed only in one reproductive organ, i. e., GbMADS9 expressed only in male reproductive organs and GbMADS10 expressed only in female reproductive organs.