What Is DNA Day?
DNA makes us human. This genetic blueprint inside our cells determines, in large part, how our bodies look and function. And because DNA is passed on from one generation to another, that same code tells the story of our family lineages and our entire species back to its earliest days. Genetics even holds much promise for a healthier future, because it lies at the core of so many potentially preventable and curable conditions.
In light of this microscopic material’s outsize importance, the National Human Genome Research Institute (NHGRI) observes National DNA Day on April 25 to celebrate the history of genetics and to promote its future. NHGRI and the Smithsonian Institution’s National Museum of Natural History will host a full calendar of events on April 19 at the museum while other organizations follow suit across the nation.
“For us DNA Day has been an opportunity to connect scientists with students and get them excited about the possibilities that exist within genetics and genomics,” explained NHGRI’s Dr. Carla Easter. “Not just from a career perspective, even though jobs will exist in ten years that none of us have thought of yet, but also how it will affect them healthwise and in other ways throughout their future lives.”
DNA Day commemorates James Watson’s and Francis Crick’s 1953 discovery of DNA’s molecular structure—the now familiar double helix—and also marks the tenth anniversary of the completion of the Human Genome Project, which occurred in April 2003.
Watson and Crick were awarded 1962’s Nobel Prize in Physiology or Medicine for their discovery, an award they shared with Maurice Wilkins. (Another major contributor, Rosalind Franklin, was not nominated, though her experimental data and photographs were key to the discovery.)
“This structure has novel features which are of considerable biological interest,” the pair wrote in a 1953 edition of the journal Nature. Over the past 60 years that tantalizing opening line has proven to be an enormous understatement.
DNA’s distinctive spiral staircase structure, which is found inside every cell, contains the genetic instruction manual for the creation of any organism.
The DNA (deoxyribonucleic acid) molecule contains four nucleotide bases: chemical units called adenine, thymine, guanine, and cytosine (but usually abbreviated as A, T, G, and C) written billions of times. The order in which these bases are grouped together on segments of DNA called genes determines many of the key biological characteristics of the organism that carries them. They guide the protein production that regulates how each of our ten trillion cells will function and combine to form tissues and organs. They help determine our eye color, size, and countless other attributes. And because DNA is passed on from parent to offspring, the many pages of this genetic book also tell the long tale of your family journey all the way back to the first ancestor of all living humans.
In total, the human genome consists of some 20,000 to 25,000 distinct genes, each one a long string of DNA, neatly packaged into 23 distinct pairs of chromosomes. This human instruction manual was revealed in April 2003 by the Human Genome Project, which created a road map of the human body’s genes and the functions they were designed to perform and then made that data available to researchers all over the world. Over the past decade that effort has helped the science of genetics advance dramatically—though experts stress it remains in its infancy.
Some of the great progress and promise of DNA lies in the realm of human health. Diseases with at least some roots in genetics, from cancer to cardiovascular disease, are responsible for a major portion of the world’s health issues. All humans are 99.9 percent identical genetically, but differences in the other .1 percent may make all the difference, including genetic mutations or abnormalities that cause diseases or make people more susceptible to them when paired with lifestyle and environmental factors.
Genetic sequencing allows scientists to pinpoint these genetic trouble spots. Often the causes of a single disease are many and complex, so unraveling them means decoding differences in nucleotide orders called single nucleotide polymorphisms, which are being ably cataloged by the International HapMap Project. That effort allows scientists to explore the causes of disease not only in individual genes but also across the entire human genome.
“We’ve been stressing the ground that we’ve gained in terms of cancer research,” said NHGRI’s Easter. “Before, scientists were thinking of cancer more simply as a disease that affected a particular part of the body. Now we’re into the molecular aspects of this disease and are even able to sequence tumors.”
Genetics can help people stay healthier before problems arise by identifying an individual’s risk factors so that lifestyle and other changes can help to keep them in good health. Those predisposed genetically to type 2 diabetes, for example, might adopt diet and exercise regimens to stay healthier.
Genetic knowledge is also driving more effective drug development. “We’re moving towards personalized medicine, using the sequences that we gain from individuals to better understand the kind of treatment that we give them,” Easter said. Pharmacogenetics and pharmacogenomics study how the variation in single or multiple genes make some people respond differently to the same medicines. As these fields advance, more drugs may be customized to the specific genetic makeup of their patients—making them much more effective and resulting in fewer side effects.
Efforts in gene therapy take the science a step further, aiming to treat disease by repairing or replacing defective genes. Though the practice is only just getting off the ground, many predict it could be curing diseases within a decade. A major sticking point, at the moment, is how to get the “correct” genes to the cells where they belong. That’s currently done by imbedding them in viruses, but it’s a problematic process.
Retracing the Past, Improving the Present
While medicine is a particularly important showcase of genetic progress, DNA is already playing a major role in other industries.
Scientists can produce altered DNA in laboratories, known as recombinant DNA, that genetic engineers use to create desirable traits in animals. Some may be engineered to produce the same kinds of traits long sought by conventional livestock breeding, like disease resistance or high growth rates. Other animals might be genetically programmed to produce substances in their blood or milk, for example, that can be used to develop human drugs. Still other livestock might become living sources of cells or tissues desired for human transplants.
Genetically modified crops have already become rather commonplace, and genetics is used to improve the yield, drought resistance, or other useful qualities of food supply. Some genetically modified varieties may even boast biological insecticides that make them more resistant to pests without the use of chemical pesticides. While today most genetically engineered goods don’t pack much nutritional advantage over their natural counterparts, that may change in the near future. One famous example is “golden rice,” pumped up with beta-carotene, that can ease vitamin A deficiency in Southeast Asia and is likely to soon be planted in that region.
And through initiatives including The Genographic Project, DNA is informing our understanding of what it means to be human. The infrequent mutations and changes in our genetic blueprint provide evidence to recreate humans’ genetic and geographic journey from the earliest modern people to their exit from Africa some 70,000 years ago, and along all various migrations that carried our species to the ends of the Earth. Similar studies have lent much clarity to the study of wildlife, illuminating the relationships between species and lineages in a way that no previous scientific discipline could.
In all these ways and many others, DNA reveals our past and promises to improve our future. To learn more about genetics and genomics, take time out to celebrate DNA Day on April 25. You needn’t be an expert. In fact, Easter touts the event as a perfect opportunity to learn more. “We think anybody and everybody should celebrate DNA Day,” she said. “It’s an exciting time to explore.