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The Genetic Journey: Following DNA from Cell to Society

The Genetic Journey: Following DNA from Cell to Society

The Genetic Journey: What's Next?

By Brian W. Simpson

Breakthroughs in the science of DNA, proteins and cell processes come at a breathtaking pace these days, but solutions to complex diseases remain frustratingly elusive. Eight experts at the Bloomberg School take stock of what we know, where we are and, most importantly, where public health research needs to go.

George Dimopoulos

"Genomics as we know it today did not exist 15 years ago. We did not have the complete DNA or genome sequences of organisms then. While the main challenge of the genomic era was to determine DNA sequences and predict genes, the challenge of the post-genomic era is to assign functions to all these genes; we now have to relate them to specific aspects of the disease and to understand what they are doing. It's like you have a book with all these words in it, but now you have to read it and understand it." George Dimopoulos

Scott Zeger

"Biology has gone from being a study of organisms and their components to being an information science. What is DNA? It's an information code. But more information does not mean more knowledge. More knowledge comes from very careful and clever analysis of information. We need to get better at this. We need better tools for acquiring information, managing it and asking questions of it. Needles are hard to find in a haystack unless you have a metal detector. That's what we need now." Scott Zeger

Sharon Krag

"In the next few years, you'll go to the doctor, and the doctor will say, 'Sharon, you have a cancer. And we know which specific genes are mutated. We can successfully treat your cancer specifically using this approach.' Treatments once relied on information about tissues and cells, but they are now based on which genes are mutated. That's what is exciting. And that is what personalized medicine means." Sharon Krag

Roger McMacken

"I hate to make predictions. Life is so complicated. They declared war on cancer in 1971. That was before oncogenes, before tumor suppressor genes. Now, we know it's a thousand times more complicated. We need to understand how things work before we can kill things like cancer selectively. I don't think we'll be shutting down our collective research efforts on cancer any time soon." Roger McMacken

Terri H. Beaty

"I think genetics has been oversold somewhat. Now that you can genotype 100,000 SNPs at a time or 500,000... How are you going to digest that much data? And when you're doing a million tests, how many times are you going to be wrong? People get carried away. They say, 'Well, gee, if we can find a gene for Huntington's disease or cystic fibrosis, can we find a gene for alcoholism or cynicism?' But they're not that simple, you know? We are still working on the mechanism so we can understand it. A lot of diseases have become a little more clear, but not perfectly clear." Terri H. Beaty

David Levin

"The existing approaches and tools of genetic epidemiology work well to identify responsible factors when you're dealing with diseases caused by a single mutation. They don't work so well for complex diseases involving multiple genetic and environmental factors—some of the major public health problems in the U.S., like obesity, heart disease and Alzheimer's. To my mind, there's a need for population-based and laboratory-based sciences to coalesce and develop new approaches to complex disease causation. The first step is to train people in interdisciplinary ways so they understand the molecular sciences as well as epidemiology and biostatistics." David Levin

John Groopman

"Humans are 99.2 percent similar to a chimpanzee, but as [Hopkins cancer researcher] Don Coffey has pointed out, no chimpanzee has ever written a piano concerto. Why is that? Well, in addition to epigenetics, it's because of our cell signaling pathways. They are truly the wiring network in our cells. When they're triggered, they lead to a specific set of expressions of genes, telling a cell to proliferate, to die, to send out new blood vessels... These signaling pathways are how a cell does all these things. I'll go out on a limb here: Most human disease is driven at the end of the day by these signaling pathways getting messed up and leading to disease too early in life." John Groopman

Ruth Faden

"We have to be thinking very broadly about how genetic information should be used—not only in a medical context, but also how that information could be used in employment settings and law enforcement settings and national security settings. Information can be useful for lots of different purposes, and the question is, which purposes are acceptable?" Ruth Faden

Faculty Sources:

Terri H. Beaty, PhD, professor, Epidemiology; Shyam Biswal, PhD, associate professor, Environmental Health Sciences (EHS); George Dimopoulos, PhD, assistant professor, Molecular Microbiology and Immunology (MMI); Lori H. Erby, PhD '06, ScM '01, assistant scientist, Health, Behavior and Society (HBS); Ruth Faden, PhD, MPH, executive director of the Johns Hopkins Berman Institute of Bioethics, the Philip Franklin Wagley Professor of Biomedical Ethics, professor of Health Policy and Management; M. Daniele Fallin, PhD, associate professor, Epidemiology; John Groopman, PhD, chair, EHS, and the Anna M. Baetjer Professor in Environmental Health; Rafael Irizarry, PhD, associate professor, Biostatistics; Wen Hong Linda Kao, PhD '99, MHS '97, assistant professor, Epidemiology; Thomas Kensler, PhD, professor, EHS; Sharon Krag, PhD, associate dean, Graduate Education and Research; David Levin, PhD, professor, Biochemistry and Molecular Biology; Roger McMacken, PhD, chair of Biochemistry and Molecular Biology and the E.V. McCollum Professor in Biochemistry; Elizabeth A. Platz, ScD, MPH, associate professor, Epidemiology; Debra Roter, DrPH '77, MPH '75, professor, HBS; Ingo Ruczinski, PhD, assistant professor, Biostatistics; Peter F. Scholl, PhD, MS, senior research associate, EHS; Alan Scott, PhD, professor, MMI; Keith West, DrPH '87, MPH '79, the George G. Graham Professor of Infant and Child Nutrition, International Health; James D. Yager, PhD, senior associate dean, Academic Affairs, and the Edyth H. Schoenrich Professor in Preventive Medicine; Yin Yao, PhD, associate professor, Epidemiology; Peter P. Zandi, PhD '01, assistant professor, Mental Health; Scott Zeger, PhD, chair of Biostatistics and the Frank Hurley and Catharine Dorrier Professor in Biostatistics.

Additional Sources

Human Molecular Genetics by Jack J. Pasternack; John Wiley & Sons, 2005 Genome: The Autobiography of a Species in 23 Chapters by Matt Ridley; Harper Perennial, 1999 , National Human Genome Research Institute, Canadian Museum of Nature genomics website, National Center for Biotechnology Information

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