SGER: The Taxonomic Distribution of Middle-Repetitive DNA Families: Homoplasy Free Phylogenetic Data?

9528964马歇尔在过去的十到十五年中，分子序列数据为研究许多不同生物群体中的系统发育关系或谱系之间的联系提供了强有力的工具。这类数据通常有助于解决传统形态数据不足或建议的替代和相互冲突的结果的关系。然而，就像形态数据包括聚合/平行衍生特征一样，相同的分子序列可以独立出现。这种汇聚或平行的特征，称为同型，如果它们不被识别，从而无意中被用来关联分类群，可能会非常有问题。该项目寻求开发一种从分子数据中消除同源基因的方法，只从“中间重复序列”中提取，从而选择性地利用罕见的基因组事件。这些(“家族”)的可识别组合将是一个谱系所独有的，因此“无同源”数据将可用于系统发育重建。这一方法将用九种海胆的DNA序列数据进行开发和测试。如果这一测试案例证实了研究者的假设，那么这项研究的结果可能会对众多分子系统学家具有非常广泛的适用性和实用性。该奖项是根据NSF的探索研究小额赠款(SGER)计划颁发的，该计划旨在资助创新的、高风险的研究，如果成功，可能会对未来的研究方向做出重大发现或贡献。如果这一特定项目的成功，开发了一种获得信息丰富的分子序列数据的精细方法，马歇尔博士将为研究新生代具有辐射的各种生物的系统学家做出潜在的有用贡献。一种更有效和更可靠的方法来获得可靠的分子系统学可以在时间和研究资金方面提供巨大的节省。

9528964 MARSHALL In the past ten to fifteen years molecular sequence data have provided powerful tools for investigating the phylogenetic relationships or associations of lineages in many diverse groups of organisms. Such data have often helped to resolve relationships where classical morphological data were insufficient or suggested alternative and conflicting results. Yet, just as morphological data includes convergent/parallel derived features, the same molecular sequence can arise independently. Such convergent or parallel features, known as homoplasies, can be very problematic if they are unrecognized and thus unwittingly used to associate taxa. This project seeks to develop a methodology for eliminating homoplasies from molecular data by drawing only from "middle-repetitive sequences", thereby selectively utilizing rare genomic events. Recognizable assemblages of these ("families") will be unique to a lineage and therefore "homoplasy-free" data will be available for phylogenetic reconstruction. This methodology will be developed and tested with DNA sequence data from nine species of sea urchins. If the investigator's suppositions are bore out with this test case, the results of this research may have very broad applicability and utility for numerous molecular systematists. This award is made under NSF's Small Grants for Exploratory Research (SGER) Program, which is designed to fund innovative, high-risk research with the potential, if successful, for major discovery or contribution to future research directions. If successful with this particular project for developing a refined methodology for obtaining informative molecular sequence data, Dr. Marshall will have made a contribution of potential utility to systematists working with a broad diversity of organisms with radiations in the Cenozoic. A more efficient and reliable means of deriving reliable molecular phylogenies can offer great savings in both time and research funds.