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

野生动物的驯化在人类社会的进化中起着重要的作用。然而，使动物适合家庭环境的特征可能使它们不适合野外生活。将驯养的动物放归野外往往会导致它们与野生表亲的广泛杂交（例如，在鱼、猪、牛、鸭、植物中），潜在地将驯化性状引入野生种群。这种杂交的后果可能包括由于野生种群的生存和繁殖减少而导致的丰度下降。绿头鸭是世界上最知名的物种之一，也是当今许多流行的家鸭品种的主要来源。不幸的是，在过去的世纪里，在北美故意释放人工饲养的野鸭，导致了野鸭与野生野鸭的广泛杂交，特别是在北美东部。该项目将研究今天不同的北美野鸭种群的遗传和形态品质，以了解杂交如何影响野生种群，以及它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、研究生和博士后一级的人力资源。这项工作也将对这种重要的猎鸟的管理和保护产生影响。研究小组将调查在景观水平上驯化和野生野鸭之间的基因流事件期间遗传物质移动的倾向。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上广泛的物种范围的样本集，并将使用博物馆标本的古代DNA方法将遗传采样扩展到过去100至150年。利用博物馆标本的3D形态测量分析，以及野生和驯养野鸭的饲养轨迹，他们将研究与驯养鸟类相关的特征的运动（例如，影响取食效果的喙形态）进入野生种群可能会影响野生种群的适应性。研究人员将致力于三个广泛的目标：（1）通过评估大约在上个世纪野生野鸭的分子变化，了解北美野鸭的家庭x野生杂交群的起源和发展时间，（2）确定基因流动与不同选择机制的组合（即，自然选择与人工选择）和人口统计学历史影响分子多样性和分歧的估计，通过比较野鸭的家养和野生变种的基因组，和（3）理解形态特征对种群生存力的潜在重要性，以及家养特征是否在野生环境中越来越普遍和适应不良，该奖项反映了NSF的法定使命，并被认为值得通过利用基金会的知识价值和更广泛的影响进行评估来支持审查标准。

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.