DISSERTATION RESEARCH: Reticulation and chromosomal evolution in Amaryllidaceae tribe Hippeastreae

该项目旨在研究一组染色体多样化的新热带开花植物--石蒜科(石蒜科)的网状进化。石蒜科菊科植物的属分类包括10-12属180种，包括石榴花、雨百合和其他观赏植物，尽管这些植物在园艺上具有重要的意义，但仍然存在争议。据推测，这群单子叶动物是一次古老的杂交事件的后代，另外，更近的杂交也混淆了进化关系。主要目的是：1)评估沙棘亚科网状进化的范围和性质；2)在系统发育的背景下探索染色体进化的模式。通过下一代测序技术获得的多个核基因的DNA序列将研究该群体的潜在进化史或系统发育。网状进化将通过考虑基因树的异质性和系统发育的网络表示的方法来解决。染色体进化将通过染色体数目变异的建模和细胞学特征(包括遗传、结构和数字差异)到进化树上的映射来评估。这个项目将通过综合分子方法对不同时间尺度和倍性水平(基因组复制)的植物进化中的网状结构提供一般见解。这项研究将为合作PI提供各种分子和细胞遗传学技术方面的重要培训机会，他将作为教师和研究人员应用于他的祖国智利。因此，他将为智利系统学研究项目的发展做出贡献，目前该领域缺乏足够的专业知识。该项目将导致对沙棘亚科植物的分类进行修订，这将使其他从事这些植物研究的科学家和园艺家受益。这一分类将被整合到eMonocot中，这是一个全球单子叶分类在线资源。

This project seeks to examine reticulate evolution in a chromosomally diverse group of Neotropical flowering plants, the Amaryllidaceae (amaryllis family). The generic classification of Amaryllidaceae tribe Hippeastreae, which includes 10-12 genera and ~180 species, including amaryllis, rain lilies, and other ornamentals, remains controversial, despite the horticultural importance of these plants. This group of monocots is putatively descended from an ancient hybridization event, and additional, more recent hybridizations have confounded evolutionary relationships. The main goals are to: 1) assess the extent and nature of reticulate evolution in Hippeastreae; and 2) explore patterns of chromosome evolution in a phylogenetic context. The underlying evolutionary history, or phylogeny, of the group will be investigated with DNA sequences of multiple nuclear genes obtained by next-generation sequencing techniques. Reticulate evolution will be addressed through methods that consider gene tree heterogeneity and network representations of the phylogeny. Chromosomal evolution will be assessed through modeling of chromosome number variation and mapping of cytological characters, including genetic, structural, and numerical differences, onto evolutionary trees. This project will provide general insights into reticulation in plant evolution at different temporal scales and ploidy levels (genome duplication) through an integrative molecular approach.This research will provide the co-PI with significant training opportunities in diverse molecular and cytogenetic techniques, which he will apply as a teacher and researcher in his home country, Chile. Hence, he will contribute to the development of systematics research programs in Chile, where this field currently lacks sufficient expertise. This project will result in a revised classification of Hippeastreae, which will benefit other scientists and horticulturists working with these plants. This classification will be integrated into eMonocot, a global online resource for monocot taxonomy.