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September 27, 2004
Genes and tea leaves
neil lamb is assistant professor of human genetics
"Genetics—that’s rather like science fiction, isn’t it?”
I was recently at a conference in Great Britain and took a side trip to Edinburgh to stroll the Royal Mile and see Edinburgh Castle and the Palace of Holyrood. Midway through the afternoon, I stopped in a teahouse for a pot of “Old Edinburgh” and a scone with jam (when in Rome…).
There I met an outgoing and friendly couple from Boston who was spending the year in London. Both in their late 50s, they had come to Edinburgh for the weekend. We struck up a conversation and, after exchanging pleasantries, they asked what had brought me to Great Britain. I explained that I was attending a scientific meeting about the genetic aspects of meiosis (the biological process that creates eggs and sperm).
At that point, the woman’s eyes lit up, and she began asking me about genetics and disease. That’s when she asked me the above question linking genetics to science fiction.
Her question gave me an opportunity to unravel some of the mystery of DNA, bring it out of the realm of fiction and into this woman’s world of reality.
I love questions like this because they give me a chance to talk about how genes influence different aspects of life and health.
I suppose this love of spontaneous scientific conversation with strangers is an extension of my love for teaching, manifest outside the traditional classroom setting. This experience, I imagine, is common for most teachers, whatever their field of interest. Additionally, as a scientist whose research depends on grants derived in large part from taxpayer dollars, I feel a responsibility to help develop or clarify an understanding of genetics and its related technology. An informed public is a well-educated one and, in the years ahead, many issues concerning DNA testing, technology and treatment will be debated, evaluated and (perhaps) regulated. So, somewhat selfishly, I want as many well-informed people as possible engaged in the discussions.
Nearly everyone I talk with has at least some knowledge of DNA—the somewhat mystical double helix that gives each of our cells the instructions to carry out specific actions and duties. Most also understand that DNA is passed from parent to child through sperm and egg. This is part of the reason we might have great-grandma’s lanky build or grandpa’s red hair.
Thanks to the popularity of television programs such as “CSI,” many people realize that DNA obtained from saliva, semen, hair follicles and so forth can be used to identify each person on our planet (unless, of course, that person happens to have an identical twin, in which case the situation gets a bit more complicated, but I’ll leave that to the genre of the soap opera). Beyond this level of knowledge, however, the understanding of genes and their function often gets murky for even the most well-educated individual.
In general, most of us ascribe too much power to the DNA strands found inside our cells, believing our genes provide the sole influence on our appearance, health and behavior. Often I hear this summed up along the lines of, “All the answers are found in our DNA, and in the near future we will be able to predict the precise course of our lives based upon the information.” A similar, equally popular scenario describes a husband and wife looking over a “menu” listing specific characteristics they may desire for their future children, creating a patchwork quilt of the ideal offspring.
It’s understandable how this view of genetic determinism has arisen. Almost daily, scientists report the identification of a gene involved in this disorder or that characteristic. At first blush, one could draw the conclusion that genes play the sole, starring role in all aspects of our lives. To be fair, there is some truth to this; the influence of genes is widespread and far reaching.
However, what fails to be communicated in the 60-second TV soundbite or the four-paragraph newspaper story is the often equally important role played by the individual’s environment. Although some diseases such as sickle cell anemia, polycystic kidney disease or cystic fibrosis can be attributed to a change (mutation) in a single gene, the severity of even these conditions usually is modified by additional genetic and environmental factors. For most traits and diseases, multiple influences shape outcome and impact.
For example, diet, level of activity, and risk factors—such as whether we smoke, take certain medications or are exposed to specific hormones as a fetus or later in life—are likely to have key influences on appearance, health and behavior. We are far from understanding the interplay between genetics and environment, and for complex traits such as personality or intelligence, there are likely to be hundreds of contributing players. (These were all things that came up in the course of my discussion in the teashop.)
In 2003, 50 years after the discovery of the DNA structure, a worldwide scientific collaboration gave us the specific sequence of the human genome (the collection of DNA found in each of our cells). This was heralded by some as the printing of “The Book of Life.” Such an amazing achievement allows scientists to identify each of the approximately 30,000 genes that make us who we are. It also represents an initial step toward determining the function of each of those genes. Additional studies will help identify the interacting environmental factors, as well.
Such progress has allowed clinicians and researchers to talk about a future era of “personalized medicine,” where health care treatments and prevention are based in part on an individual’s genetic predispositions (determined from a reading of that person’s DNA sequence), coupled with specific environmental risk factors. Treatments will be tailored to each individual’s unique combinations, identifying the most effective medication or treatment with the lowest incidence of side effects, or highlighting environments to avoid or embrace for maximum health.
As we move toward this vision, we must tread carefully. There are numerous ethical, legal and social issues intertwined within the strands of DNA. Concerns over genetic testing and privacy, the risk of genetic discrimination, the cost and availability of genetic technologies and their use in screening or even “designing” of future generations—all must be given serious consideration. These issues also were part of our teatime discussion.
And so, on a beautiful Sunday afternoon, in the shadow of a medieval fortress, I found myself drawn into a lively discussion of our genes and their environmental partners, the promise of future diagnosis and treatment, and how we must thoughtfully proceed into this exciting new world. We talked for nearly an hour, and as the conversation drew to a close, we agreed that while, yes, some of these concepts do sound a bit like science fiction, they are quite likely to become a standard part of reality.
We parted company, passing a table where another couple also looked into the future—this time, however, by finding hidden meaning in the pattern of tea leaves swirled at the bottom of a china cup. I thought about asking the couple if they had ever heard of genetic testing but, letting the impulse pass, turned instead onto the cobblestone street and became a tourist once more.