AWARDEE: Paul Siegel
FEDERAL FUNDING AGENCIES: Department of Agriculture, National Science Foundation
Imagine a single science experiment – run by a single scientist – for 65 years and counting. Paul Siegel doesn’t have to imagine it. He lives it. Siegel, 90, still visits nearly every day the Virginia Tech lab where he began his seminal work with chickens in 1957. That’s when Siegel began breeding two lines of chickens, one high-weight and one low-weight; those lines continue today, along with another longtime set of lines related to immunity. This work is well-known to poultry scientists throughout the world and serves as a foundation for modern methods of raising and breeding chickens, a major global food source. The impact of Siegel’s work on humans, rather than chickens, is perhaps his most profound contribution: he has trained and mentored hundreds of students throughout his distinguished career.
Paul Siegel with his high- and low-weight chickens (John McCormick, Virginia Tech)
The Chicken Guy
Siegel, a self-proclaimed “chicken guy,” grew up on a 32-acre farm in Connecticut, where his family grew tobacco and raised chickens. He was fascinated by the chickens and began observing their breeding – seeing, for example, what feather colors emerged from the offspring of different pairings. In 1949, he was recognized in a U.S. Department of Agriculture (USDA) “Chicken of Tomorrow” contest for “outstanding achievement in breeding and development of superior meat-type chickens.”
When he was 10 years old, he met a poultry geneticist at the University of Connecticut, Dr. Walter Collins, whose job sounded a lot like what Siegel was doing for fun on the farm. Siegel was hooked. “I asked him how to do it as a career, and he said you need a Ph.D. I didn’t even know what a Ph.D. was,” he recalls.
That changed after he studied first at Collins’ university and later at Kansas State University, where he earned his doctorate and then went on the job market. His first – and last – job interview was at Virginia Tech. After joining the faculty in 1957, he has been coming to campus ever since.
Siegel as a young researcher
Diverging Lines
Shortly after beginning his role at Virginia Tech, Siegel initiated a pedigreed growth selection study, selecting birds for either high or low body weight when the birds were eight weeks of age. (Meat-type chickens are marketed at a fixed weight, Siegel says. At the time, they were marketed at twelve weeks of age, and eight weeks seemed absurd. Today, it is six weeks or less.) With some restrictions, birds with the highest weights were used as parents of the next generation for the high-weight selected line, whereas those with the lowest weights were used for the low-weight selected line. The biology of the lines is remarkable – today the average weight of the birds in the high-weight selected line is nearly twelve times the average weight of those in the low-weight selected line. Even more remarkable is that Siegel has selectively bred and maintained the lines continuously for more than 65 generations (years).
Several years later, he initiated another long-running experiment, this time involving a chicken’s immune response, where he separated chickens into high- and low-immune function lines.
Early support for the lines came from Hatch Act funds, a federal agricultural funding program that also involves state matching funds, and USDA regional research funds, now called USDA Multistate Funds, which have offered critical long-running support. Siegel has also received grants from the USDA’s National Institute of Food and Agriculture and the National Science Foundation. In addition, he has worked with the U.S.-Israel Binational Agricultural Research and Development Fund.
“He never gave up on those birds,” says Mary Delany, Professor Emerita of Developmental Genetics at the University of California, Davis. “He can fight the fight. He had to continue to convince the university of their value.” Virginia Tech even named its poultry research center after Siegel in 2010, and Siegel continues to serve as University Distinguished Professor Emeritus there.
A Global Food Source
In the mid-1950s, when Siegel began his work, chicken was not the food staple it is today. Throughout much of American history, chicken was considered a meal fit only for Sunday dinners or special occasions. Due in part to changes in the way farmers raised their flocks, consumers’ food storage practices, and cultural norms, chickens are now a global food powerhouse. From the commercial companies that cultivate broilers (chickens raised for their meat) and layers (chickens raised for their eggs) to the resurgence of backyard breeding, and to native and indigenous stocks around the world, chickens are a cost-effective source of protein.
Back then, a chicken raised on a farm would require more than three pounds of feed for every pound of its own weight, according to Bob Taylor, Professor of Animal and Nutritional Sciences at West Virginia University. Today, though a chicken can grow to twice the size, it eats less than two pounds of feed per pound of its weight. Siegel’s work was integral to this change.
It comes down to something called the resource allocation model, Taylor explains. “The best way I can describe it is if you have a fully electric car: the electricity and battery go to run the motor or motors that drive the wheels, but there are other things in that car that draw on that electricity and take away from the ability to run the motor, like the heater, A/C, radio, phone charger. All of those things draw away from the ability of the battery to run the motor. Not that they all can’t occur at the same time, but rather, the way they are used determines how long a motor will run to drive the car.”
Similarly, Siegel and his long-running experiments have shown how different factors in a chicken – such as changes in body weight or immunity – can affect other parts of a chicken’s life, such as how much feed it eats, how much physical strength it has, how robust its immune function is, or how well it breeds with other chickens. Understanding this balance has helped chicken producers in a growing industry.
Siegel as a child on his family’s farm
Siegel’s curiosity about resource allocation stemmed from his early years. “There are finite resources, and I knew from growing up on a farm that there are only so many chickens and so many eggs. Which way is it going to go? What are the tradeoffs? You have to be able to understand the whole interplay.” He also credits his upbringing with honing his abilities to take care of his chickens and maintain the lines smoothly over so many years. “It’s mostly instinct,” he points out. “You can be a natural athlete, but you still need a sense of what to do. Luck favors the prepared.”
Layers of Learning
While Siegel’s experiment continued unabated for decades, it contributed to scientific breakthroughs as human scientific understanding advanced. His famous lines have been featured in publications such as National Geographic and Nature; in the latter, he co-authored a paper identifying key genetic markers in chickens. “His early work was understanding growth and immune response,” says Delany. “Then it evolved to the metabolism. Science kept changing, and soon you could get to the cellular and molecular level. Then there’s a genetic layer and an environmental layer. You could study these lines for a more holistic approach to health in chickens, on obesity, eating behavior and disorders, bone health, and the humane treatment of animals. More recently, the studies have turned to inputs related to climate changes and how animals respond to changes in those inputs.”
According to the Food and Agriculture Organization (FAO) of the United Nations, “world poultry meat production soared from 9 to 133 million tonnes (metric tons) between 1961 and 2020,” representing a 4.67 percent annual increase over 60 years. “Certainly, some of that change can be attributed to scale-up across the poultry industry,” Taylor says. “I think that Dr. Siegel’s genetic selection studies helped make this change achievable. Food production efficiency is already important, and it will become more so as the world experiences an increasing need for food production to meet the demand created by population growth.”
Taylor estimates that as of 2021, the wholesale value of poultry products worldwide reached around 90 billion dollars. Though it’s hard to directly quantify Siegel’s contributions, Taylor says, “Even if his impact was only 1 percent, a conservative estimate, that’s 900 million dollars. I would call that pretty significant.”
What stands out to Delany in addition to Siegel’s contributions to the field is his love for his research subjects. “There’s an animal at the end of the DNA strand,” she says. “Paul understood them on a cellular level, their metabolism, their DNA – but he never forgot about the animal.”
Siegel and Lab Specialist Christa Honaker (Jane W. Graham)
The Individual is the Impact
Siegel is most proud of the impact he’s had on his students and trainees. He estimates he’s served as a major advisor for about 50 graduate students and hundreds of undergraduate and graduate students. “I was so lucky to work with smart people,” he says.
Nick Anthony studied under Siegel – an experience that inspired him to start his own lines at the University of Arkansas, where he spent many years before going into the poultry industry.
It was exciting – and exacting – work. A student of Siegel’s had to be constantly on alert. “We had to simultaneously watch the pens and count the number of times the male mounted the female and how many times successful mating took place. It taught the students to be observant. You introduce a lot of chaos when you introduce a high-mating bird. It taught me to be a better bird biologist and bird behaviorist, and to focus on what that bird is telling you.”
Now at Cobb-Vantress, a global poultry company, Anthony has conversations informed by Siegel’s work. For example, the poultry industry used to routinely administer antibiotics to chickens to enhance growth and protect them from disease. Now, with modern knowledge of how this practice can contribute to antibiotic resistance, chicken producers and purchasers are increasingly moving away from it. “If you can select for disease resistance, you can reduce the number of antibiotics in the program,” he says. “It just shows how relevant he was, how ahead of the game.”
Notably, Siegel was “an early leader in what we might call the diversity movement,” says Taylor. “He had grad students of various backgrounds – ethnic, religious, gender, the whole thing. You name a category, and they were likely represented among his students.” This sentiment is echoed by several of Siegel’s other colleagues and collaborators.
Siegel has also made it a practice to send eggs to scientists who have wanted to work with them in their own experiments. “If they wanted to study the birds, they could have the birds,” says Delany. “He is very generous in spirit.”
One of those scientists is Leif Andersson at Sweden’s Uppsala University. Working together and with a team of collaborators, Andersson and Siegel conducted a buzzworthy study indicating that evolution can happen 15 times faster than previously believed. Siegel’s lines played a pivotal role.
Indeed, the impact of the lines has been felt worldwide, says Anthony. “Hundreds of researchers have benefited from his program,” he says. Siegel can name several countries where he has collaborated on cooperative research involving direct use or knowledge gained from his lines, including Sweden, Israel, China, Malaysia, Peru, Brazil, France, Italy, England, Turkey, Ghana, Hungary, Japan, Germany, and the Netherlands.
It was also common for grad students from abroad to come to Virginia for brief periods to work with the lines. Often, they would stay at Siegel’s house, which became affectionately known as the “Siegel Hilton.” Recalls Siegel, “It was a win-win, because our children became exposed to other cultures and foods.”
Siegel (522 Productions)
A Basket of Golden Eggs
Siegel’s work has been recognized by multiple agricultural organizations, including in the International Poultry Hall of Fame. To date, he has over 600 scientific journal publications on topics as wide-ranging as immune function, reproductive biology, feed efficiency, single genes and genome evolution, neurobiology, muscle and adipose biology, nutrition and metabolism, stress biology, and bone health. His long-term selected lines have contributed to the molecular, cellular, tissue, and organismal levels of scientific understandings of the genetics and inheritance mechanisms in numerous fields – a basket of golden eggs.
Beyond his peers in agricultural science and genomics, Siegel has received accolades in the broader scientific community, including election as an honorary fellow of AAAS (which houses the Golden Goose Award). He has served as president of the Poultry Science Association, Animal Behavior Society, Virginia Academy of Science, and the American Institute of Biological Sciences.
A bobblehead of Siegel and his chickens, which sits on Siegel’s desk
As to what motivated him to carry out a 65-year experiment – and counting – it was, in large part, the excitement of the unknown. “I never knew what the next generation [of chickens] was going to give me,” Siegel says. “If I knew what I was doing, it wouldn’t be science. That’s the joy of science.”
However, he says, “I see individuals as my impact” – meaning his work as a teacher, mentor, colleague and collaborator. Siegel is now retired, but for the past 20 years, he has continued to visit his lab nearly every day. He wouldn’t have it any other way: “I’m very, very fortunate.”
By Erin Heath