William and Mary Alumni Magazine | Spring 2008, Vol. 73, No. 3
Photo by Mark Mitchell
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Mary-Lou Pardue '55 has never followed convention. So when she began her keynote address at the College's 2008 Neuroscience Symposium on "Exploring the Genome," the first slide she presented was not a high-tech image of a DNA molecule. Instead, she showed a medieval map.
"Even the most completely assembled genome is like this early map," Pardue told her large audience of students and faculty. "The mapmakers would create highly intricate drawings of the areas they knew. The parts they didn't know they left blank, with the label 'Here there be dragons.'
"I'm here today to talk about some of the dragons," she said.
For a half-century, Mary-Lou Pardue has ventured into the terra incognita of science, confronting dragons -- and slaying more than a few of them. As the Boris Magasanik Professor of Biology at the Massachusetts Institute of Technology, she's earned an international reputation for her work on the structure and function of chromosomes. She was elected to membership in the National Academy of Sciences in 1983, considered one of the highest honors that a scientist can be accorded, and has served as president of both the American Society of Cell Biology and the Genetics Society of America.
And as a female scientist who broke through the glass ceiling, she's blazed a trail for new generations of women to follow.
From Frogs to Fruit Flies
Pardue's science journey began at William and Mary. "I didn't apply anywhere else," she says, explaining that she'd fallen in love with the campus while on a family trip to Williamsburg. "I thought it was the most beautiful college I'd ever seen."
Although she was certain about her university choice, she was less sure about a major, taking everything from English to Ancient Greek during her first two years and having "a wonderful time." Then came the end of sophomore year. "It was a choice between biology and engineering," she says. Engineering meant she'd have to leave William and Mary. "I decided to major in biology, which is what I think I wanted to do all along."
Although she hadn't yet taken any biology courses, she quickly made up for lost time. "The faculty were so accommodating: they let me take courses as co-requisites rather than prerequisites." Pardue singles out J.T. Baldwin '32, a botanist and chair of the biology department, and assistant professor Grace Blank as being especially supportive. Her aptitude for biology was readily apparent, and she worked as a teaching assistant for several courses, including physiology. She remembers that many students, including some otherwise stalwart football players, were squeamish about the process of pithing frogs to prepare them for dissection (this in the days before stricter protocols for lab animals). Pardue calmly stepped in. "I think they were very glad for the help," she says.
Pardue's visit back to William and Mary in February -- her first in several decades -- allowed her to appreciate how much the campus has changed since her undergraduate days. "Students spend so much more time in the lab now," she told the audience at an Introduction to Women's Studies class. "We didn't even have individual research projects when I was here."
In fact, when Pardue's campus host, John Griffin -- associate professor of biology and director of the neuroscience program -- brought her to the now-outdated Millington Hall, she gently reminded him that Millington hadn't even existed when she was a student. Her biology classes were held in Washington Hall.
Scientific study isn't the only thing that's changed at the College. "I'm amazed to see all the women in pants," Pardue told students. "When I was here you couldn't walk across campus in pants unless you had a raincoat on.
"If you were really daring," she added, "you flashed your raincoat open."
In the mid-1950s, few women graduated from college with an academic career in mind. Pardue's professors urged her to apply to graduate school, and although she received a number of fellowship offers, she turned them down. "I was looking for more adventure, plus I'd never seen a woman with a Ph.D. in a job I wanted," she explains.
Instead, Pardue took a job as a technician at Oak Ridge National Laboratory in Tennessee. By a twist of fate, she ended up working with a group of scientists studying genetics. It was at Oak Ridge that Pardue was introduced to Drosophila genetics, and she's studied the fruit fly ever since.
"It was the best thing that could have happened," she says. "They treated me like a graduate student." Her mentors again urged her to go to graduate school. She first earned an M.S. in radiation biology at the University of Tennessee in 1959. Then, wanting to continue her studies of the molecular biology of chromosomes, she successfully applied to the doctoral program at Yale University.
But, she adds, "Becoming a professor was still beyond my consideration."
"Women Have to Work a Little Harder"
When Pardue arrived at Yale in 1965, she went to work in the lab of Professor Joseph Gall, who was studying the largest known chromosomes, found in the oocytes of amphibians, named "lampbrush chromosomes" by 19th-century scientists who thought they resembled the brushes used to clean lamp chimneys.
For her Ph.D. thesis, Pardue devised a groundbreaking technique called in situ hybridization -- essentially the process of unwinding the two strands of one DNA helix and creating a hybrid molecule by introducing RNA or DNA from another source, with the amount of hybrid serving as a measure of the similarity of the DNA of the two sources. As Pardue explains, "It allowed you to compare DNA sequences, telling you how one source is related to the other. In other words, is this animal like that animal?"
In situ hybridization is now one of the most widely used techniques in molecular biology. "I got out my Ph.D. thesis before Professor Pardue's visit," says W&M Professor of Biology Lizabeth Allison. "There at the beginning, in Figure 2, was in situ hybridization." Allison's graduate school mentor at the University of Washington, Aimee Bakken, knew Pardue well and introduced her to Allison early on. "It was such a positive reinforcement for my own career to see these very strong women and what was possible," Allison notes.
When Pardue received her Ph.D. in 1970, the job market was tight and she didn't expect to get a faculty appointment. Instead, she traveled to the University of Edinburgh for two years of postdoctoral research. By 1972, the academic world had begun to open its doors a little wider for women: the Ivy League schools, for example, finally began admitting female students to their undergraduate programs.
With letters of support from such luminaries as Professor Don Brown of the Carnegie Institute, Pardue began to be approached by universities. "I got lots of interviews -- I surprised myself."
MIT offered her a position as an associate, rather than assistant, professor of biology, and she took the job. "There were already two women on the faculty in the department of biology, so I knew I wasn't going to be just a token," she says. (Nevertheless, her appointment was still somewhat of a novelty: Pardue notes that when she spoke at a symposium on women in science at Princeton shortly afterward, the highest-ranking female faculty member at the host university was an acting instructor.)
"MIT's been a great place for me," she says. Throughout her 35-year career there, she's continued to do more groundbreaking work. Studying how cells respond to stress, her laboratory was the first to identify the dramatic change in cellular RNA brought about by heat shock. In her long-term study of telomeres -- the ends of chromosomes -- she's discovered that the lowly fruit fly maintains the ends of its chromosomes by means of special transposable elements. Pardue speculates that these telomere elements may be evolutionary precursors of viruses.
Despite all of the advances for women in academia, the female professors in MIT's School of Science still noticed subtle and not-so-subtle differences in treatment. "In general, as we've gotten older, all of us have come to realize that women have to work a little harder," Pardue says.
"In the early 1990s, we decided it was time to do a serious study of what happens to women when they get to MIT." Headed up by Pardue's colleague Nancy Hopkins, the study found quantifiable evidence of bias. "The dean and the president responded," Pardue says. "The change that impressed me most was that the president increased the pensions of women faculty who had already retired."
Challenges remain, however. Pardue highlights a great cause for concern among academic scientists: "Women do very well in graduate school and in postdocs, but we don't see them in faculty positions." Pardue and her colleagues are attempting to identify solutions to this "black hole at the end of postdocs." Among them are putting more women on search committees and adopting more family-friendly policies for younger faculty.
The study of gender differences was the main topic of Pardue's visiting lecture to the College's Introduction to Women's Studies class. A study on sex differences in health that Pardue chaired for the National Academy of Sciences concluded that there are "multiple, ubiquitous differences in the basic cellular biochemistries" between males and females.
The issue is how to recognize that fact without providing ammunition for improper discrimination.
As one student asked at the end of Pardue's talk, "How do we deal with the fact that science has been used to justify racism and sexism?" Pardue acknowledged the difficulties: "We're going to be dealing with that question for the rest of my life, and probably for the rest of your lives as well."
Still Going Strong
Since Mary-Lou Pardue began her career, the changes in science -- and for women in science -- have been revolutionary. "When I walked out of Yale, I could not have believed that we would be sequencing genomes now." The revolution has come about not through a single breakthrough, but by the steady, assiduous work of scientists like Pardue.
Pardue's return to William and Mary inspired an upcoming generation of scientists who will build on her legacy. But she's not done yet. As Professor Liz Allison, whose students joined Pardue for lunch during her visit, notes, "My students were amazed that after 50 years, she's still going strong, still publishing these exciting papers. You can see her eyes light up when she talks about her research."
After all, there are more dragons to slay. Asked by a student if she wanted to study other insects, the ever-modest Pardue responded: "I'd like to get the courage."
She added, with a twinkle in her eye, "I'd love to work on mosquitoes."
