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

杂交、渐渗（基因通过杂交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。一个清晰的系谱树，描绘物种关系，是理解这些现象的基础，但构建起来可能极具挑战性。这项研究有两个目的。第一个是发展解决这种系谱树的策略。第二个是使用这些方法来解开马鞭草复合体的进化历史，这是一个以杂交、渐渗和多倍化的流行为特征的群体。通过比较叶绿体和核基因组中四个独立的DNA区域的序列，构建系谱树来推断亲缘关系。此外，数以百计的转座因子（西内斯和MITE），即可以在染色体上从一个位置移动到另一个位置的遗传因子，将被识别出来并用于追踪宿主生物的进化历史。预期的成果包括一个清晰的马鞭草复合体进化树，它将被纳入阿根廷达尔文研究所植物学家的最新分类学处理中。利用转座元件追踪植物进化历史是植物进化研究中的一个新的应用，可能对植物进化研究产生重大影响。这项研究的结果将在年度科学会议上发表，并提交给同行评审的期刊发表。

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.