DISSERTATION RESEARCH: Untangling the Evolutionary History of the Verbena Complex (Verbenaceae): Hybridization, Introgression, and Polyploidization

杂交、导入(通过杂交将基因从一个物种转移到另一个物种)和多倍化(染色体加倍)是植物物种形成和进化中的重要现象。一棵解析良好的谱系树，描述物种之间的关系，是理解这些现象的基础，但构建起来可能极具挑战性。本研究有两个目的。第一个是制定解决这类系谱树的策略。第二种方法是用这些方法来解开马鞭草复合体的进化历史，马鞭草复合体是一个以杂交、渐渗和多倍化盛行为特征的群体。通过比较叶绿体和核基因组中四个独立DNA区域的序列，将构建系谱树来推断亲缘关系。此外，数以百计的转座元件(精氨酸和螨虫)，即在染色体上可以从一个位置移动到另一个位置的遗传元件，将被识别并用于追踪承载它们的有机体的进化历史。反解放的成果包括一棵分辨良好的马鞭草复合体进化树，它将与阿根廷达尔文研究所的植物学家合作，纳入最新的分类治疗。利用转座子追踪进化历史是植物进化研究的一种新应用，可能会对这类研究产生重大影响。这项研究的结果将在年度科学会议上公布，并提交给同行评议的期刊发表。

Hybridization, introgression (movement of genes from one species into anothervia hybridization), and polyploidization (chromosome doubling) are importantphenomena in plant speciation and evolution. A well-resolved genealogical tree,depicting the species relationships, is fundamental to understand these phenomena, butcan be extremely challenging to construct. This research has two aims. The first is todevelop strategies for resolving such genealogical trees. The second is to use thesemethods to untangle the evolutionary history of the Verbena complex, a groupcharacterized by the prevalence of hybridization, introgression, and polyploidization. Bythe comparing sequences of four independent DNA regions from the chloroplast andnuclear genomes, genealogical trees will be constructed to infer relationships. Inaddition, hundreds of transposable elements (SINEs and MITEs), genetic elements thatcan move from one location to another on chromosomes, will be identified and used totrace the evolutionary history of the organisms that host them.Anticipated outcomes include a well-resolved evolutionary tree of the Verbenacomplex, which will be incorporated into an updated taxonomic treatment incollaboration with botanists at the Instituto Darwinion, Argentina. Using transposableelements to trace evolutionary histories is a novel application to plant evolutionarystudies and may have great impact on such studies. Results from this research will bepresented at annual scientific meetings and submitted to peer-reviewed journals forpublication.