COLLABORATIVE RESEARCH: Genomic and Morphological Consequences of Landscape-Level Hybridization between Wild and Domesticated Congeners

驯化野生动物在人类社会的进化中很重要。然而，使动物适合在家中生活的特征可能会使它们不太适合野外生活。将驯养动物放生到野外往往会导致与野生近亲(例如，鱼、猪、牛、鸭、植物)进行广泛的杂交，有可能将驯化特征引入野生种群。这种杂交的后果可能包括数量减少，因为野生种群的生存和繁殖减少。绿头鸭是世界上最知名的物种之一，也是当今许多受欢迎的家鸭品种的主要来源。不幸的是，上个世纪北美人工饲养的绿头鸭被故意放生，导致了与野生绿头鸭的广泛杂交，特别是在北美东部。这个项目将研究今天不同的北美绿头鸭种群的遗传和形态质量，以了解杂交如何影响野生种群，以及它可能如何影响该物种未来在野外的生存能力。该项目将有助于开发本科生、研究生和博士后各级的人力资源。这项工作也将对这种重要的猎鸟的管理和保护产生影响。研究小组将在景观水平上调查家养和野生绿头鸭之间基因流动事件中遗传物质的移动倾向。他们将把一套全面的分子技术应用于来自当代种群的地理范围广泛的物种样本集，并将使用博物馆标本的古代DNA方法将遗传采样延长到100到150年前。他们将利用博物馆标本的3D形态计量分析，以及用活的野生和驯养的绿头鸭饲养的小径，研究与驯养鸟类相关的特征(例如，影响觅食效率的喙形态)进入野生种群的移动可能如何影响野生种群的适应性。研究人员将致力于解决三个广泛的目标：(1)通过评估大约上个世纪野生绿头鸭的分子变化，了解北美野生绿头鸭杂交种群的起源和发育时间；(2)通过比较绿头鸭的家养和野生变种的基因组，确定不同选择机制(即自然选择与人工选择)的基因流和人口历史组合如何影响分子多样性和多样性的估计；以及(3)了解形态特征对种群生存的潜在重要性，以及驯化特征是否在野生环境中日益普遍和不适应，通过评估野鸭的家养和野生变种之间的形态和觅食效率差异。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Domestication of wild animals was important in the evolution of human societies. However, traits that make animals suitable in domestic settings can make them poorly suited for life in the wild. The release of domesticated animals into the wild often results in widespread hybridization with their wild cousins (e.g., in fish, pigs, cows, ducks, plants), potentially introducing domesticated traits into wild populations. The consequences of such hybridization could include declines in abundance because of reduced survival and reproduction of wild populations. The mallard duck is one of the most recognized species in the world, and has been a primary source for many of today’s popular domestic duck breeds. Unfortunately, the intentional release of captive-reared mallards in North America over the last century has resulted in widespread hybridization with wild mallards, particularly in eastern North America. This project will examine the genetic and morphological qualities of today’s distinct North American mallard populations in order to understand how hybridization has affected the wild populations, and how it may affect the species' future viability in the wild. This project will contribute to the development of human resources at the undergraduate, graduate and post-doctoral levels. This work will also have implications for the management and conservation of this important game bird.The research team will investigate the propensity for genetic material to move during gene flow events between domesticated and wild mallards at a landscape level. They will apply a comprehensive set of molecular techniques to geographically broad species-wide sample sets from contemporary populations, and will extend genetic sampling 100 to 150 years into the past using ancient DNA approaches with museum specimens. Using 3D morphometric analysis of museum specimens, as well as feeding trails with live wild and domesticated mallards, they will examine how the movement of traits associated with domesticated birds (e.g., bill morphologies that affect feeding efficacy) into wild populations may affect the adaptability of wild populations. The researchers are set to address three broad aims: (1) Understanding the origins and timing of development of a domestic x wild hybrid swarm of mallards in North America by assessing molecular changes in wild mallards over approximately the last century, (2) Determining how the combination of gene flow with varying selective regimes (i.e., natural versus artificial selection) and demographic histories affect estimates of molecular diversity and divergence, by comparing the genomes of domestic and wild variants of the mallard, and (3) Understanding the potential importance of morphological traits for population viability, and whether domesticated traits are both increasingly prevalent and maladaptive in wild settings, by assessing morphological and foraging efficiency differences between domestic and wild variants of the mallard.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.