Building a better human

Scientists equipped with the secrets of the human genome are getting closer to cures for diseases and longer life spans

Building a human
(Image credit: Corbis)

How has technology affected human biology?

The transformation has just begun, but it has already produced startling results. Researchers, for example, have created the equivalent of an ink-jet “printer’’ that uses tubes of cells instead of an ink cartridge to create thin layers of human skin. In time, the technique will help burn victims heal using skin produced from their own cells. Researchers have “printed” a mouse heart, which momentarily beats on its own after receiving an electric shock. In labs around the world, scientists are progressing toward radical new medical treatments by manipulating sections of gene code— removing targeted genes or modifying them by introducing foreign DNA. Researchers are even learning how genes can be turned “off” or “on.” As an example of what may be possible, a herd of genetically modified goats in Massachusetts is producing an otherwise costly anti-clotting drug free of charge—in their milk.

What’s driving all this innovation?

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Our rapidly evolving understanding of life itself. Two developments have been key: the sequencing of the human genome and advances in stem-cell research. The genome, the biological code that runs human hardware, took 10 years and $3 billion to sequence. And just as computer processing has been subject to Moore’s Law, with power doubling every two years as the price of computing plummets, the cost of sequencing an individual’s genes has fallen to about $10,000 and is sinking fast. “We’ve seen as much as 100,000-fold reduction in cost over as little as five or six years,” says George Church of the Personal Genome Project.

What does genetic analysis produce?

Medical treatments personalized to the individual. The human body’s more than 20,000 genes are arrayed in a sequence of 3 billion pairs. Researchers at Yale University last fall announced that by selectively analyzing just 1 percent of the genome—the genes that code for proteins—they could identify disease-causing mutations in a timely and cost-effective manner. They used genetic analysis to diagnose a rare congenital disease in a patient whose condition had been misdiagnosed. In the near future, scientists may even be able to reverse or inhibit genetic aberrations that lead to disease. One team of researchers is compiling a Cancer Genome Atlas to catalog the means by which healthy cells become cancerous—the first phase in developing treatments to alter such processes. “What we’re seeing is the birth of a new biology,” says Eric Green, director of the National Human Genome Research Institute. “We’re learning how the parts work together and figuring out what each one of them is doing.”

Where are the magic cures?

They’re coming. The U.S. Food and Drug Administration recently approved the first clinical trial of a human embryonic stem-cell therapy, allowing Geron Corp. to use stem cells to treat patients with spinal cord injuries. No one expects instant success. But the hope is that stem cells injected into the damaged area of the spine will adapt and multiply, renewing the damaged zone and providing insights into how to perfect the therapy. “In 20 years, we will have stem cell banks like pharmacies,” says David Warburton of the Saban Research Institute. “You will get a specific diagnosis and take a specific type of stem cell.” Meantime, scientists are using cells to produce pig hearts, rat livers, and mice teeth that grow independently in a lab. Anthony Atala, director of the Wake Forest Institute for Regenerative Medicine, grows human bladders, and has implanted more than two dozen of them in human patients since 2006.

How do you grow a bladder?

Atala builds a scaffold, which he calls a “cell delivery vehicle,” and then coats it with healthy cells from a patient’s bladder and incubates it. The cells multiply, expanding across the scaffold, eventually forming a new bladder that can be implanted. Since the bladder is derived from the patient’s own cells, the body doesn’t reject it. Hollow organs are easier to create than solid ones, but researchers have recently made strides with livers, hearts, and even lungs. Major challenges remain. But sometime in the future, scientists hope, humans will be able to mimic the processes that enable other animals to regenerate body parts. When a salamander loses a leg, it sprouts a new one. A zebra fish can even regenerate a portion of its heart. Humans can regenerate bones and skin, but like other higher species, lost the capacity to regrow limbs and organs during the process of evolution. By manipulating specific genes, scientists may turn this miraculous power back on.

How would that affect life expectancy?

In a world in which aging or diseased people can swap a damaged heart, liver, or other organ for a new one created from their own DNA, a majority of children alive today might live to 100 or beyond. It’s hard to know how far-reaching the effects might be because we’re still only at the dawning of the biological revolution. But true believers have seen enough to predict changes of historical import. “We’re beginning to understand how life is coded and how life makes things,” says bio investor Juan Enriquez. “How we make things, where we make things, is going to change on a scale similar to that of the Industrial Revolution. It’s already happening.”

The synthetic future

When scientist Craig Venter recently announced the creation of the world’s first synthetic cell, life on earth changed, literally. Genetically modified products are nothing new—more than three-quarters of the world’s soybean crop is genetically modified. But by inserting computer-designed genetic material into a bacteria cell, Venter’s team created an entirely new strain of bacteria—a new life form. ExxonMobil has already signed a $300 million deal with Venter’s Synthetic Genomics to design an algae that produces liquid fuel, and other synthetic life, like a bacteria programmed to make biodegradable plastic, is anticipated. In announcing his invention, Venter called it the first life on earth “whose parent is a computer.”

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