Dissertation Research: Systematics of Palm Subtribe Oncospermatinae

9902082 Doyle和刘易斯棕榈科已被公认为一个独特的组植物在整个记录的历史，但分类和系统发育之间的关系，ca。200属仍然不清楚，是世界各地的一小群专家继续研究的主题。 在包含槟榔科、可可科、地诺马亚科和下荷贝亚科的谱系中，辨别112个属之间的关系特别困难。 研究生卡尔刘易斯与其他研究人员合作，在康奈尔大学杰夫道尔博士的监督下，正在进行槟榔亚族Oncospermitinae的系统发育研究，这是一组8属，包括分布在印度洋岛屿和邻近陆地上的估计12个物种。 形态学数据和DNA序列将用于解决亚族内的关系，并评估组的不同地理假设。 也将确定亚族Oncospermitinae的系统发育位置，并将研究结果整合到整个谱系内的关系的新兴假设。 形态观察收集标本和活的棕榈在外地，这些数据支持的假设，亚族Oncospermitinae是一个自然的血统。 从叶绿体基因组内两个不同的DNA区域获得序列数据，这两个区域通常用于低分类水平的系统发育研究。 不幸的是，这些区域的变化不足以提供棕榈属之间关系的信息。 为了寻找更适合本研究的DNA数据，研究人员开发了用于扩增和测序编码苹果酸合酶的核基因的大内含子的引物（EC 4.1.3.2），该基因以前未用于系统发育研究。 初步数据显示，苹果酸合酶内含子是一个很好的来源，棕榈树的系统发育信息，有足够的核苷酸替换，以区分属。将对重要的Oncosperma属进行更有重点的调查，该属包含五个或更多的物种，分布在东南亚沿海和岛屿的广阔地区，目标之一是该群体的综合分类学专著。

9902082Doyle and Lewis The palm family has been recognized as a distinct group of plants throughout recorded history, but taxonomic and phylogenetic relationships among the ca. 200 genera are still unclear and are the subject of continuing study by a small group of specialists worldwide. It has been particularly difficult to discern reationships among the 112 genera within the lineage containing tribes Areceae, Cocoeae, Geonomae, and Hyophorbeae. In collaboration with other researchers working on portions of this lineage, graduate student Carl Lewis, under the supervision of Dr. Jeff Doyle at Cornell University, is conducting a phylogenetic study of Areceae subtribe Oncospermatinae, a group of eight genera comprising an estimated 12 species distributed on islands and neighboring landmasses of the Indian Ocean. Morphological data and DNA sequences will be used to resolve relationships within the subtribe, and to evaluate different biogeographic hypotheses for the group. The phylogenetic position of subtribe Oncospermatinae will also be determined, and the findings will be integrated into emerging hypotheses of relationships within the entire lineage. Morphological observations were collected from herbarium specimens and from living palms in the field, and these data support the hypothesis that subtribe Oncospermatinae is a natural lineage. Sequence data were obtained from two different DNA regions within the chloroplast genome that are commonly used in phylogenetic research at low taxonomic levels. Unfortunately, these regions are not variable enough to provide information about relationships between palm genera. In a search for DNA data more suitable for this study, the investigators have developed primers for amplifying and sequencing a large intron of the nuclear gene encoding malate synthase (EC 4.1.3.2), which has not been used previously in phylogenetic research. Preliminary data show the malate synthase intron to be a good source of phylogenetic information in palms, with sufficient nucleotide substitutions to discriminate among genera. A more focused investigation will be conducted on the important genus Oncosperma, which contains five or more species occurring over a broad region of coastal and insular southeast Asia, with one goal being a comprehensive taxonomic monograph of the group.