"It's like Star Wars," a woman with the Huntington's disease mutation recently told me. This lethal gene had killed her relatives in every generation for hundreds of years, but she could now test her embryos to ensure that her children do not get it. "I don't understand it all," she told me, "but the peace of mind is huge."
This week marks the 10th anniversary of the completion of the Human Genome Project, the successful mapping of the entire human genome, the 3 billion molecules that are the blueprints for us as human beings. This event ranks with NASA's response to Sputnik as one of the great achievements of modern science supported by public funds. Over the past decade, researchers have continued to make incredible strides, discovering genes associated with diabetes, depression, schizophrenia, bipolar disorder and other diseases. The future possibilities are enormous.
But we should use this anniversary as an opportunity not only to celebrate but to reflect. These miraculous discoveries also present us with countless dilemmas and are far outpacing our abilities to grasp and address their ethical, legal and social implications. The genome is far more complicated than anyone imagined. The more we learn, the more we realize how much we don't know. Uncertainties and controversies abound.
Mice have about 20,000 genes, so scientists initially thought humans must have at least 50,000 to 150,000. In fact, we have about the same number as rodents and flies. We share 99.9 percent of our genes with each other, 80 percent with dogs and 69 percent with chickens. Rice has more genes than do humans (46,000), because our system is more parsimoniously designed.
Over the past 10 years the costs of sequencing a human genome have also plummeted from $100 million per person to less than $1,000. As a result, more people are getting sequenced, and medical centers are trying to gather and store this information on as many patients as possible in huge biobanks. These data can help researchers find genes associated with diseases and successful treatments. Eventually doctors will be able to choose certain medications for each of us based on our unique genomes, so-called "personalized medicine."
Yet genetic discoveries can also be patented, earning hundreds of millions of dollars for private companies and sometimes universities. Myriad Genetics, for instance, owns the patents for the breast cancer genes and charges over $3,000 for these tests. Unfortunately, as a result, millions of women around the world cannot afford them.
For patients who can pay, doctors can now use genetic tests to screen embryos and fetuses for ever more diseases. Some patients can eliminate certain deadly mutations, such as that for Huntington's, from their descendants. But doctors and patients increasingly face quandaries regarding which diseases to test for and remove. For instance, many physicians and patients are screening out embryos with a breast cancer mutation, though these genes wouldn't cause symptoms until adulthood and would do so only about 50 percent of the time.
The wealthy are thus eliminating certain diseases from their descendants, while the poor cannot, widening the gap between the haves and the have-nots. For example, parents may soon abort fetuses that have a 20-percent chance of developing autism. Some doctors say that in the near future, they will be able to select embryos that will have blond hair and blue eyes. This billion-dollar industry is largely unregulated by the government. As a society, we are thus confronting quandaries of whether federal or state governments or professional medical organizations should ban some of the practices, and if so, which and how.
Unfortunately, understanding of genetics among physicians, patients and policymakers also remains low. Media headlines still announce "The Fat Gene," "The IQ Gene," "The Gay Gene," "The Addiction Gene" and "The God Gene." Beliefs in "genetic essentialism" (the idea that single genes cause common diseases and traits) persist. In fact, most lethal mutations cause only very rare diseases. Common diseases such as diabetes and asthma appear to result from complex interactions of multiple genetic and environmental factors. The human genome evolved to resist the effects of single lethal mistakes. Multiple, not single, genetic errors are usually needed to kill us.
In addition, most doctors don't fully understand how to incorporate genetics into practice, and may over- or under-order tests. Doctors who graduated from medical school before the Human Genome Project started differ markedly from later graduates.
Genetic discrimination also perseveres, at times fueled by misunderstandings. The 2008 Genetic Information Nondiscrimination Act (GINA) covers health insurance but not disability insurance, life insurance or long-term care insurance. Some patients still face subtle discrimination at work too, such as being passed over for a promotion because they have a mutation.
Other controversies continue, as well, from how many genetic tests to perform on pregnant women and newborns to whether to genetically modify more animals and plants.
On this anniversary we should celebrate the incredible advances of the past 10 years, but we should also begin to prepare ourselves for the next decade. No one could have foreseen how far science has progressed. What seemed science fiction is now reality. Yet we now need not only research but more public and professional education about it, as well as attention to how it is affecting our lives and how it should affect our lives. Sputnik prompted the federal government to support not only research but science education, putting billions of dollars in our educational system.
The science of genetics is evolving more quickly than our understanding of it. We need to strive further to keep up.
A version of this essay appeared on the Oxford University Press Blog.