SG: Is Pollinator Discrimination Among Populations of the Southwestern Desert Creosote Bush Differing in Chromosome Number Promoting Speciation?

本研究将探讨多倍体在开花植物多样化的作用，通过研究传粉者的偏好和繁殖的相互作用，植物之间的染色体互补性不同的沙漠灌木杂酚油布什（Larrea tridentata）。确定一个物种变成两个物种的过程对于理解生物多样性的模式和生态系统的功能至关重要。物种形成，新物种形成的过程，发生在种群或群体之间的繁殖障碍。然而，研究具有多个染色体组的开花植物物种的物种形成-一种被称为多倍性的条件-已被证明是困难的。大多数开花植物是多倍体，染色体数目不同的群体不易杂交，但它们很少被认为是不同的物种。其原因包括不同染色体数目的植物之间的物理相似性，以及它们是否适应了不同的环境。虽然杂酚油布什与不同的染色体互补栖息在生态不同的地区，他们有时共同出现，表明额外的生殖障碍负责分歧。通过结合DNA分析、温室实验和实地调查，该项目将为具有不同染色体互补的植物群体的物种形成早期阶段提供前所未有的见解。该研究的总体目标是通过阐明基因组复制对植物多样化的生物学意义，将多倍体物种纳入更大的物种形成研究范围。多倍性，特别是同源多倍性，其中基因组复制发生在一个谱系内，而不是通过杂交，对进化生物学家提出了许多挑战，包括理解生态和内在遗传过程对多样化的相对重要性。种群水平的分析是至关重要的，以评估植物-动物的相互作用和生态适应的影响分歧之间的“种内”群体不同的染色体互补，以及是否多元化的多倍体物种是类似的模式二倍体物种。此外，该项目，重点是关键植物物种Larrea tridentata及其本地传粉者在敏感的北美沙漠生物群落，将有助于表征新的分子多样性和生态相互作用，包括多倍体物种的神秘生物多样性。对染色体互补性不同的种群的分类识别可能会显著改变世界某些地区的生物多样性估计，特别是温带生物群落，影响我们对主要生态模式的理解。

This research will investigate the role of polyploidy in flowering plant diversification by studying pollinator preferences and reproductive interactions between plants differing in chromosome complement in the desert shrub creosote bush (Larrea tridentata). Determining the processes by which one species becomes two is crucial to understanding patterns of biodiversity and the functioning of ecosystems. Speciation, the process of new species formation, occurs when barriers to reproduction evolve between populations or groups. However, studying speciation for flowering plant species with multiple chromosome sets - a condition known as polyploidy - has proven difficult. Most flowering plants are polyploid, and groups with different chromosome numbers cannot easily interbreed, yet they are rarely recognized as different species. Reasons for this range from the physical similarity between plants with different chromosome numbers, to whether they have adapted to different environments. Although creosote bush with different chromosome complements inhabit ecologically distinct areas, they sometimes co-occur suggesting additional reproductive barriers are responsible for divergence. By combining DNA analyses, greenhouse experiments, and field investigations, this project will provide unprecedented insight into the early stages of speciation for groups of plants with different chromosome complements.The overarching goal of this research is to bring polyploid species under the larger umbrella of speciation research by elucidating the biological significance of genome duplication to plant diversification. Polyploidy, especially autopolyploidy, where genome duplication occurs within a lineage rather than through hybridization, poses many challenges for evolutionary biologists, including understanding the relative importance of ecological and intrinsic genetic processes to diversification. Population-level analyses are critical for evaluating how plant-animal interactions and ecological adaptation influence divergence among "intraspecific" groups differing in chromosome complement, and whether diversification of polyploid species is similar to model diploid species. Moreover, this project, focused on the keystone plant species Larrea tridentata and its native pollinators in sensitive North American desert biomes, will help characterize the novel molecular diversity and ecological interactions comprising the cryptic biodiversity of polyploid species. The taxonomic recognition of populations differing in chromosome complement could significantly alter biodiversity estimates for certain parts of the world, especially temperate biomes, impacting our understanding of major ecological patterns.