Phylogenetic and Molecular Evolutionary Investigations of Chloroplast DNA Variation in the Campanulaceae sensu stricto

9982091 Jansen基因组(DNA)数据正在帮助对生物的分类关系、分类和进化从属关系的研究产生革命性的影响。除了DNA序列数据(来自可比或同源基因的核苷酸串)、限制酶切位点数据和其他类型的基因顺序数据也是有价值和强大的证据来源。德克萨斯大学的Jansen博士在植物系统发育关系分析中的限制酶切位点和基因顺序方法方面一直处于领先地位。在这个项目中，他和他的同事们将研究风铃花科植物(风铃花科)，其中叶绿体基因组拥有所有开花植物家族中已知的最大范围的结构或基因顺序变异，包括倒位、IR区的扩张/收缩(所有陆地植物叶绿体基因组的反向重复特征)、基因转位、基因丢失和大开放阅读框架内的缺失。预计这些变化中的大多数在分子水平上即使不是独一无二的，也是罕见的，因此可能是家族内亚系的潜在标记。然而，在许多情况下，建议的重排必须通过终点或其他“热点”的直接核苷酸测序来确认，以确保对等变化的比较。因此，该项目将分子进化领域的分析与努力相结合，努力构建桔梗科属30-50属的框架系统发育图，并改进对这些属的分类。詹森博士正在与世界各地的同事和收集者网络合作，以保护该科所有已知属的样本，并在风铃属和瓦伦贝贾属等大型属中扩大样本。与以前的学生和其他同事一起，收集了大量的初步数据。来自叶绿体和核基因的DNA序列数据正在被收集，以产生独立于重排证据的系统发育，并与传统分类学研究中的形态特征相结合。最近受训的该小组专家威廉·埃迪博士来自苏格兰，他可能会加入德克萨斯州的实验室，带来叶绿体matK基因的分子系统分析数据和形态专业知识。成功地确定桔梗科叶绿体基因组重组过程中的结构事件序列将有助于改进属的分类，为该科的历史生物地理学包括众多岛屿特有物种的起源提供洞察，并有助于理解花型和授粉的进化。

9982091Jansen Genomic (DNA) data are helping to revolutionize the study of taxonomic relationships, classification, and evolutionary affiliations of organisms. In addition to DNA sequence data (strings of nucleotides from comparable, or homologous, genes), restriction-site data and other kinds of gene-order data are also valuable and powerful sources of evidence. Dr. Jansen at the University of Texas has been a leader in the development of restriction-site and gene-order methods in the analysis of phylogenetic relationships of plants. In this project he and a team of colleagues will study the plant family Campanulaceae (the bellflower family), where the chloroplast genome has the greatest known range of structural or gene-order variants of any flowering plant family, including cases of inversion, expansion/contraction of the IR region (the Inverted Repeat characteristic of all land plant chloroplast genomes), gene transpositions, gene losses, and deletions within large open reading frames. Most of these changes are expected to be rare if not unique events, at the molecular level, and are thus potentially strong markers of sublineages within the family. In many cases, however, the proposed rearrangements must be confirmed by direct nucleotide sequencing of end points or other "hot spots" to ensure comparison of equivalent changes. The project thus combines analyses in the field of molecular evolution with efforts to construct a framework phylogeny for the 30-50 genera of Campanulaceae and an improved classification of these. Dr. Jansen is working with a network of colleagues and collectors around the world to secure samples of all of the known genera of the family, and extended samples within the large genera such as Campanula and Wahlenbergia. Abundant preliminary data have been gathered, in conjunction with former students and other colleagues. DNA sequence data from both chloroplast and nuclear genes are being gathered to generate a phylogeny independent of the rearrangement evidence, and to integrate with morphological characters from traditional taxonomic studies. A recently trained specialist on the group, Dr. William Eddie from Scotland, will likely join the laboratory in Texas, bringing both data from molecular systematic analyses of the chloroplast matK gene and morphological expertise as well. Success in determining the sequence of structural events in repatterning the chloroplast genome of Campanulaceae will help improve generic classification, provide insight to historical biogeography of the family including origins of the numerous island endemics, and help in understanding the evolution of floral form and pollination.