Q & A with Daniel L. Hartl, Recipient of the 2019 Thomas Hunt Morgan Medal.

The Genetics Society of America's Thomas Hunt Morgan Medal honors researchers for lifetime achievement in genetics. The recipient of the 2019 Morgan Medal is Daniel Hartl of Harvard University, who is recognized for his influential and diverse contributions to genetics research. The unifying theme of Hartl's broad impacts on transmission, population, evolutionary, and medical genetics has been the combination of theoretical insights with cutting-edge experimental techniques. Some of his contributions include revealing the genetics of segregation distortion, developing statistical frameworks for estimating the effects of selection, application of these frameworks to natural and experimental populations, discovery of the mariner transposon and its influence on genome evolution, insights into the evolution of gene expression differences, and modeling the evolution of malaria parasite populations. Hartl is also known as a supportive mentor who has trained many prominent geneticists that continue to shape the field.

Why Did You Choose to Study Genetics?

I’ve never been quite sure whether I chose genetics or genetics chose me! Whichever it was, genetics combines chemistry, mathematics, statistics, and biology in a way that I find deeply satisfying. I’m also attracted by how genetics highlights the role of chance in shaping our lives. I don’t mean only the randomness of Mendelian segregation and recombination, but also the chance environments that influence how hereditary traits are expressed, especially complex traits. I’d also include accidents of time and place that can change our lives. In my case, my family’s meager finances would have made it impossible for me to attend college, but on October 4, 1957 Sputnik was launched. I was 14 years old and I remember my father and I watching it streak overhead in the night sky. This event jolted Congress out of its indifference to education, and, in 1958, the National Defense Education Act was signed into law. The act provided funding for education focused on the sciences and included college scholarships. A few years later I was one of the fortunate recipients.

I was encouraged to apply by a superb high school teacher, Robert W. Meyer, who not only convinced me that I could succeed but also told me that my limits would be those that I imposed upon myself. He also inspired my best friend and many others. A voracious reader, he could walk briskly while reading a book. That skill was unusual at the time, but today you see walkers everywhere engrossed in their smartphones.

Where Did You Choose to Go to College?

I enrolled at the Marathon County Extension Center of the University of Wisconsin in Wausau. The scholarship didn’t include room and board, and this choice allowed me to live with my parents in nearby Antigo. I commuted the 34 miles in a well-used 1956 Plymouth Savoy bought for me by my three brothers who had pooled their savings (it had sporty tail fins and a pushbutton transmission). The teaching staff at U.W.–Wausau was excellent. The mathematics curriculum was transformative for me because I was wisely advised to forget everything I had learned in high school and start over. The class in creative writing was so good that for a while I seriously considered writing as a career. French got my attention when the instructor amiably informed me that I wasn’t working as hard as he expected, and that he’d give me an A if I shaped up or an F if I didn’t. (One might call this grading on a curveball). Anyhow, 2 years later I transferred to University of Wisconsin at Madison.

What Was U.W.–Madison Like When You Were There?

At that time U.W.–Madison was arguably the best place in the world to study genetics (it still is outstanding.) Many of the faculty members were young and eager, some hardly older than myself. Senior members of the faculty included four who were eventually awarded the Thomas Hunt Morgan medal, namely, Alexander Brink, James F. Crow, Oliver Smithies, and Sewall Wright. In the fall of 1963, I enrolled in a genetics course taught by James F. Crow, and it was then that I found my vocation. Professor Crow eventually became my Ph.D. mentor. I’ve written a tribute recounting my adventures in Madison and my everlasting indebtedness to him, which you can read in GENETICS (Hartl 2011). The 1960s were the heyday of molecular genetics. At that time Crow’s group included Carter Denniston, Takeo Maruyama, Etan Markowitz, and Rayla Greenberg Temin. In an adjoining laboratory was William M. Gelbart. There were also visitors who stayed for several weeks or months including Motoo Kimura, Yuichiro Hiraizumi, Terumi Mukai, Elaine Johansen Mange, and Arthur Mange. Nobelist H. J. Muller visited for a semester and taught a course in evolution, and there was a constant stream of outstanding geneticists who came to give seminars, among them Barbara McClintock and J. B. S. Haldane. Nothing as exciting came along until the genomics revolution in the 1980s.

When I left Madison for a postdoctoral position, Crow sent me a goodbye letter that typifies his generosity of spirit. It said “Now that you are leaving, let me say that I have been completely delighted with your whole career as a graduate student. You have been able to combine an experimental and theoretical program of high quality, all done promptly and with a minimum of supervision from me. It’s been a most pleasant working relation for me and I’m sorry to see it close—but that’s progress, I guess.”

Where Was Your Postdoctoral Position?

It was at the University of California, Berkeley working with the cytogeneticist Spencer W. Brown. He had studied with Barbara McClintock, and he too was an inspiration. We often took a bag lunch up the Berkeley hills and exchanged ideas while walking the paths of the arboretum. I was astonished that he seemed to know the scientific and common name of every accession as well as its native habitat, life history, and as often as not, its chromosome number.

After my postdoctoral work I landed a faculty position at the University of Minnesota in St. Paul, and from there I transposed (so to speak) to Purdue University, to Washington University School of Medicine in St. Louis, and finally to Harvard.

What Are You Most Proud of in Your Career?

I’m proudest of the achievements of the superb graduate students, postdoctoral fellows, and visiting colleagues who constituted my research group. I’ve prepared a list (Table 1) and hereby apologize to anyone I might have overlooked. The group is incredibly diverse—geographically, ethnically, and in every other way I can think of—and proof that diversity builds strength.

Table 1

Former students and postdocs

	Former students and postdocs
James W. Ajioka	Oluwakemi Amodu	Luciana O. Araripe
Francisco J. Ayala	Julian F. Ayroles	Trevor Bedford
Douda Bensasson	Susan W. Biel	Justin P. Blumenstiel
E. Fidelma Boyd	Kyle M. Brown	Glenn J. Bryan
Carlos D. Bustamante	Pierre Capy	Mauricio Carneiro
John P. Carulli	Cristian I. Castillo-Davis	Duccio Cavalieri
Belinda S. W. Chang	Hsiao-Han Chang	Diana Childress
Thanat Chookajorn	Andrew G. Clark	Russ B. Corbett-Detig
Marna Costanzo	Rachel F. Daniels	Olga Danilevskaya
Daniel De Aguiar	Antony M. Dean	Mark A. DePristo
Robert DeSalle	Erik B. Dopman	Robert F. DuBose
Jack F. Dunne III	Daniel E. Dykhuizen	Pierre Fontanillas
Dan Garza	Kerry A. Geiler-Samerotte	Yasuhiro Go
Barry G. Hall	Elisabeth Hauschteck-Jungen	David S. Haymer
Matthew Hegreness	James W. Jacobson	Pan-Pan Jiang
Hans Jungen	Szymon Kaczanowski	Nizam P. Kettaneh
Sarah B. Kingan	Akihiko Koga	Fedya A. Kondrashov
Dan E. Krane	Rob Kulathinal	Christian R. Landry
Jeffrey G. Lawrence	Bernardo Lemos	Anna Li
Rubing Liang	Danne-Anders Lidholm	Marjorie A. Liénard
Allan R. Lohe	Elena R. Lozovsky	Laurel Mapes Branstrator
Lene Martinsen	Kyoko Maruyama	Meetha M. Medora
Colin C. Meiklejohn	Rossella Milano	Raymond D. Miller
Horacio Montenegro	Etsuko N. Moriyama	Tendai Mutangadura
Javaregowda Nagaraju	So Nakagawa	Yumiko Nakajima
Kalsang Namgyal	Daniel E. Neafsey	Alexander A. Neyfakh
Karre M. Nielsen	Dmitri I. Nurminsky	Howard Ochman
C. Brandon Ogbunugafor	Atsushi Ogura	John Parsch
Dmitri A. Petrov	Jenny Y. Pham	Ana Rita Ponce
Jose M. Ranz	Benjamin L. Rice	Stephen M. Rich
Scott A. Rifkin	Rebekah L. Rogers	Scott W. Roy
Timothy B. Sackton	Stanley A. Sawyer	Nancy J. Scavarda
Mark L. Siegal	David A. Smoller	David T. Sullivan
Yun Tao	Katarzyna Tomala	Jeffrey P. Townsend
Cristina P. Vieira	Jorge Vieira	Daniel M. Weinreich
Wesley Wong	Jun Zhao	Martine M. Zilversmit

I’m also proud to have gained the partnership and trust of several long-term collaborators, all of them excellent scientists in their own right, including Elena R. Lozovsky, Daniel E. Dykhuizen, Stanley A. Sawyer, Eugene I. Shakhnovich, Sarah K. Volkman, and Dyann F. Wirth.

What Has Changed Most in Genetics During Your Career?

The research methods and resources available today could hardly have been imagined when I started graduate school. These include high-throughput, low-cost genome sequencing and a trillion-fold increase in computational power capable of handling petabytes of data. These technical advances have revitalized every aspect of experimental and theoretical population genetics from uncovering ancestry to identifying genetic risk factors for disease. A basic understanding of population genetics has become essential in parts of medicine, agriculture, and epidemiology, as well as in all areas of evolutionary biology. Ironically, as the research tools become more powerful, the problems you choose to tackle also become harder. The result is that you’re always balanced on the edge of what you’d like to do and what you’re able to do.

Let me also add that teaching methods have improved, too, especially in recent years. Today there’s much more emphasis on teaching science as a process, on scientific reasoning and how scientists use models and simulation, on mastering skills including hands-on data analysis and representation in graphs and charts. There’s also greater emphasis on assessments, active learning, in-class activities, and encouraging student self-awareness in the learning process.

I’ve authored or coauthored several textbooks in successive editions, and what with the rapid advances in genetics and innovations in teaching, there’s never been a shortage of revisions to be made. I enjoy writing about genetics. It’s never easy, but it’s been worth the effort because it’s given me the chance to play a small role in the genetics education of tens of thousands of students all over the world.

Anything More You’d Like to Add?

Yes. It is that I would be worthless without the love and support of my family who somehow learned how to deal with a nerdy, distracted, preoccupied, or absent husband and father. The specifics will have to go into the Acknowledgments. The reason is that my mother taught me never to talk too much about myself, and at this point I can imagine her spirit signaling that it’s time to stop.