Evolution and diversification of red flowers: Testing the macroevolutionary causes of rarity

进化生物学家长期以来一直试图解释生命之树中特征的分布，特别是为什么有些特征很常见，而另一些特征却很罕见。具有某一性状的分类群的数量在很大程度上是由向该状态和离开该状态的过渡率以及具有该性状的分类群的多样化率决定的。该项目将测试这些宏观进化力量在塑造马铃薯科（茄科）红花分布中的作用。虽然红色花的分类群分布在13个属中，但它们非常罕见，仅占该科约2850种中的1%。利用系统发育、解剖学和生物化学方法，本项目将(1)确定茄科植物红色的起源和机制基础，(2)验证红色花朵因多样化率降低而仍然罕见的假设，以及(3)研究这种影响是否取决于所涉及的发育途径。这项研究将为趋同进化过程中所采用的发育途径的范围以及这些机制对谱系进化成功的影响程度带来新的见解。此外，该项目所针对的植物色素对人类具有重要的健康益处，了解它们在花中的进化可能会增加提高相关作物植物（如马铃薯和番茄）色素含量的潜力。作为这个跨学科项目的一部分，高中生、研究生和本科生研究人员以及博士后助理将接受培训，该项目涵盖植物生物化学和统计比较方法。这些学员还将参加当地的外展活动，以提高K-12学生对植物生物学的兴趣。

Evolutionary biologists have long sought to explain the distribution of traits across the tree of life and, in particular, why some traits are common while others remain rare. The number of taxa with a given trait is shaped largely by the transition rates toward and away from that state as well as the diversification rates for taxa with the trait. This project will test the role of these macroevolutionary forces in shaping the distribution of red flowers in the potato family, Solanaceae. Although red-flowered taxa are spread across 13 genera, they are extremely rare, accounting for only 1% of the roughly 2850 species in the family. Using phylogenetic, anatomical, and biochemical methods, this project will (1) identify the origins and mechanistic basis for red coloration in Solanaceae, (2) test the hypothesis that red flowers remain rare due to reduced rates of diversification, and (3) examine whether this effect is contingent on the developmental pathway involved.This research will bring new insight into the range of developmental pathways employed during convergent evolution and the extent to which those mechanisms affect the evolutionary success of lineages. Moreover, the plant pigments targeted by this project have important health benefits for humans, and understanding their evolution in flowers may lead to increased potential for improving pigment content in related crop plants (e.g., potato and tomato). High school students, graduate and undergraduate researchers, and postdoctoral associates will be trained as part of this interdisciplinary project, which spans plant biochemistry to statistical comparative methods. These trainees will also participate in local outreach events to promote interest in plant biology among K-12 students.