Three mallards; photo credit: Environmental Biology grad Ryan Chelius, 2019

NSF Grant Looks at Genetic Diversity

08/19/2020

Professor Michael Schummer of the SUNY College of Environmental Science and Forestry (ESF) is a co-principal investigator for a multi-disciplinary team of researchers from ESF, the University of Texas El Paso, Mississippi State University, Smithsonian Institute, and Illinois Natural History that has received nearly $1 million in funding from the National Science Foundation (NSF) to study genetic diversity in North America. The research project is entitled "Genomic and Morphological Consequences of Landscape-Level Hybridization between Wild and Domesticated Congeners."

"Eastern North American mallard populations are declining," said Schummer, senior research associate and Roosevelt waterfowl ecologist. "We hypothesize that efforts to save the species - raising birds in captivity for ultimate release in wild environs - have actually reduced the genetic diversity of the mallard and caused the population to shrink on the East Coast."

The research team will use ancient DNA techniques on museum species to pinpoint the approximate time that the genetic shift began to occur. The ESF research team also will feed wild and domestic mallards various natural foods, documenting the efficiency with which the food is consumed. The project will be complete when the Smithsonian uses a 3-D scanner to document the size and shape of 21st century mallards' bills as compared to historic mallard specimens.

"We're looking to demarcate the shift from wild ancestry to game farm ancestry," said Schummer. "Genetically, the mallard population on the East Coast is dangerously shallow. Birds grown in captivity for release are artificially selected to grow faster, which means they are smaller."

Researchers have also documented a change in the morphology of the mallard's bills.

"Their bills are taller, shorter, and the thin membrane that their ancestors used to strain foods has changed - the lamellae," said Schummer. "Historically, mallards were likely able to strain a wider variety of foods, which helped them grow. Larger females, for instance, were better suited to lay eggs and sit on nests. Today's mallards - those raised in captivity - are smaller with bills that are best suited to eat corn and pellet feeds."

Researchers are using the mallard as a model organism, but recognize that this study has the potential to be used as a model for other species, with results that may be applied to future genetic conservation programs.

"For decades, we have initiated programs designed to save wildlife by stocking and releasing animals," said Schummer. "We theorize that in many cases, we're not preserving the genetic diversity at all. We're creating an entirely new, domesticated lineage. We must take great care to ensure that we maintain genetic diversity, even in captive programs."