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起着重要的作用。然而，使动物适合家养环境的特征可能使它们不适合野外生活。将驯养动物放归野外往往会导致它们与野生近亲（如鱼、猪、牛、鸭、植物）的广泛杂交，从而可能将驯化的性状引入野生种群。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。绿头鸭是世界上最受认可的物种之一，也是当今许多受欢迎的家鸭品种的主要来源。不幸的是，在上个世纪，北美故意放生圈养的绿头鸭导致了绿头鸭与野生绿头鸭的广泛杂交，特别是在北美东部。该项目将研究当今独特的北美绿头鸭种群的遗传和形态特征，以了解杂交如何影响野生种群，以及它如何影响该物种在野生环境中的未来生存能力。这个项目将有助于发展本科生、研究生和博士后的人力资源。这项工作也将对这种重要的狩猎鸟类的管理和保护产生影响。研究小组将在景观水平上调查遗传物质在驯化野鸭和野生野鸭之间的基因流动事件中移动的倾向。他们将应用一套全面的分子技术，从地理上广泛的当代种群中获取物种范围内的样本集，并将利用博物馆标本的古代DNA方法，将基因采样扩展到100到150年前。通过对博物馆标本的三维形态计量学分析，以及野生和家养野鸭的喂养路径，他们将研究与家养鸟类相关的特征（例如，影响喂养效率的喙形态）在野生种群中的迁移如何影响野生种群的适应性。研究人员将解决三个主要目标：(1)通过评估大约上个世纪野生绿头鸭的分子变化，了解北美家养与野生杂交绿头鸭群体的起源和发展时间；(2)通过比较家养和野生绿头鸭的基因组，确定基因流与不同选择制度（即自然选择与人工选择）和人口统计学历史的结合如何影响分子多样性和分化的估计；(3)通过评估野生鸭和野生鸭的形态和觅食效率差异，了解形态性状对种群生存能力的潜在重要性，以及驯化性状在野生环境中是否越来越普遍和不适应。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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.