RUI: Molecular and Morphological Phylogenetic Systematics of Extant and Fossil Characeae (Charophyta)

[407606 . McCourt]在一个有趣且具有挑战性的应用分子和形态数据来解决系统发育问题中，德保罗大学的Richard McCourt教授将研究被称为石藻的藻类群，即Charophyta。研究人员将通过核苷酸测序的方法，对所有现存的7个属的代表进行基因分析，以获得物种间突变差异的数据。与法国古植物学同事合作获得的相同分类群的形态特征以及这些藻类化石形式的丰富记录数据将与DNA结果相结合，以重建蕨类植物的系统发育关系。对于藻类而言，叶藻相对较大且复杂；它们在枝条的顶端有生长区，鞭毛精子细胞更像某些陆地植物，而不是其他绿藻。作为在系统发育上最接近陆地植物的藻类类群之一，叶藻可能表现出进化适应，这将有助于了解陆地植物起源的变化顺序。同时，它们的化石记录提供了一个校准基因分子变化速率的机会。

9407606 McCourt In an intriguing and challenging application of both molecular and morphological data to a problem in phylogeny, Professor Richard McCourt at DePaul University will be studying the algal group known as stoneworts, the Charophyta. Representatives of all seven genera of living members of the group will be analyzed for a number of genes by nucleotide sequencing methods, to acquire data on mutational differences among the species. Morphological features of these same taxa along with data on the rich record of fossil forms of these algae, acquired in collaboration with French paleobotanical colleagues, will be integrated with the DNA results to reconstruct the phylogenetic relationships of the charophytes. The charophytes are relatively large and complex for algae; they have growing regions at the apex of branches and flagellated sperm cells that are more similar to those of certain land plants than to other green algae. As one of the algal groups closest phylogenetically to the land plants, the charophytes are likely to show evolutionary adaptations that will help understand the sequence of changes in the origin of land plants. As well, their fossil record provides an opportunity to calibrate rates of molecular change in genes.