Long-term Natural Selection and Adaptive Introgression in Weedy Sunflowers

杂交（不同物种之间的交配和异花受精）是一种普遍的自然现象，但它在进化中的作用仍然存在争议。 它是否是一种适应不良的力量，通常会导致像骡子这样不育的、没有出路的个体？ 还是说它经常有助于适应和进化的多样化？ 提出了一种新的方法，比较长期的进化变化的实验混合和非混合控制线在该领域。 这些杂交株系是由一种经过充分研究的野生向日葵的亲本杂交而成的，旨在重现古代自然杂交的早期阶段。 杂交是否可以增加适应和表型变化的速率将通过跟踪5-10代的杂交和对照群体中的适合度、性状和数量性状基因座（QTL）来检查。 通过比较普通花园中的品系，将进化变化与表型可塑性区分开来。 在杂交系统的变化的长期可预测性将通过评估是否实验杂交收敛表型和基因型上的自然hybrid后，他们modeled.The拟议的研究是第一个实验领域的研究，以检查杂交的影响，在多个世代的适应性进化在一个野生（非作物）系统。 该补助金支持的研究将通过年度推广计划和小学生向日葵教学模块影响K-12和大学水平的科学教育。 该项目将通过培训10名本科生，3名研究生和2名技术人员来整合研究和教育。 根据PI实验室目前的人口，超过一半的学生参加这项补助金将来自科学代表性不足的群体。

Hybridization (mating and cross-fertilization between different species) is a widespread natural phenomenon, yet its role in evolution is still debated. Is it a maladaptive force, usually resulting in sterile, dead-end individuals like mules? Or does it regularly contribute to adaptation and evolutionary diversification? A novel approach is proposed that compares long-term evolutionary change in experimental hybrid and non-hybrid control lines in the field. The hybrid lines, intended to recreate the early stages of an ancient natural hybridization, are derived by crossing the parents of a well-studied wild sunflower. Whether hybridization can increase rates of adaptation and phenotypic change will be examined by tracking fitness, traits, and quantitative trait loci (QTL) in the hybrid and control populations over 5-10 generations. Evolutionary change will be distinguished from phenotypic plasticity by comparing the lines in common gardens. The long-term predictability of change in hybrid systems will be examined by assessing whether the experimental hybrids converge phenotypically and genotypically on the natural hybrid upon which they are modeled.The proposed research is the first experimental field study to examine the impact of hybridization on adaptive evolution over multiple generations in a wild (non-crop) system. The research supported by this grant will impact science education at the K-12 and university levels, through annual outreach programs and a sunflower teaching module for elementary school students. The project will integrate research and education by training ten undergraduate students, three graduate students, and two technicians. Based on the current population of the PI's lab, more than half of the students participating in this grant will be from underrepresented groups in the sciences.