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

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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.