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Copyright, 1997, Los Angeles Times. Reprinted by permission.
Wednesday, April 30, 1997
Gene Sleuths Seek Asthma's Secrets on Remote Island
hen it steamed out of Cape Town at midnight last Sept. 27, heading
for the world's "loneliest island," the South African Navy supply ship
Drakensberg carried a few unusual passengers: gene hunters.
They were headed for Tristan da Cunha, a grass-ringed volcano rising 6,700 feet out of the South Atlantic halfway between Africa and South America.
The 40-square-mile island is home to a few hundred hardy souls, most of them descended from the British sailors who settled there in 1817. Tristanians are primarily known for their cheerful resilience, collectible postage stamps and the big crawfish they catch, which American restaurants turn into "South African lobster tail."
But to a handful of geneticists, the islanders are known for a medical problem that one might not expect to find thousands of miles from the pollution and stress of urban life: They are plagued by asthma. Evidently, at least one of Tristan's founding fathers was afflicted, and his asthma-susceptibility gene or genes were passed down through the inbred generations, according to Dr. Noe Zamel, a University of Toronto medical geneticist who first studied the disease on Tristan in 1993.
Since then, there has been a boom in commercial genetics research, and Zamel's asthma study is no longer just an academic pursuit. When he went to Tristan on the Drakensberg last fall, a U.S. biotechnology company was also on board.
Sequana Therapeutics of La Jolla is working with Zamel and his colleagues to pinpoint genes underlying the islanders' asthma. Though the disease is extraordinarily common there--half of the islanders have symptoms--the scientists believe that the disorder is similar to that elsewhere.
Finding the genetic basis should lead to broadly applicable insights into the complex disease, and that information may lead to new treatments. Sequana has agreed to sell any gene discoveries it makes on Tristan to a German drug company. Sequana chief scientist Timothy Harris said the company may make an official announcement about its Tristan research within months.
If nothing else, this far-flung project underscores the epic scope of human genetics research today. Although Dolly the sheep--the first mammal cloned from a single adult cell--symbolizes a new era in science's dominion over reproduction, Sequana's voyage to one of the world's remotest human societies is emblematic of a new scientific enterprise, what might be called the human gene industry.
Sequana is one of eight public U.S. biotech companies dedicated to prospecting for valuable genes among the roughly 100,000 in the complete human set, or genome. These "genomics" firms, no more than 4 years old, promise to enhance and possibly transform medicine with drugs, diagnostic tools--and a torrent of theories about what makes us tick.
The companies have sprung up in the wake of the gargantuan federal undertaking known as the Human Genome Project. Started in 1990, the government-led effort expects by 2005 to map all the human genes strung along the 23 pairs of chromosomes. It also aims to decode the exact chemical sequence of the DNA making up those genes--a set of instructions spelled out in some 3 billion chemical units. To suggest the accelerating pace of discovery, one disease gene was discovered in 1989; last year, there were at least 21.
The genomics explosion is creating dilemmas and controversies. Critics have accused Sequana of "biopiracy" for exploiting Tristanians to gain access to their potentially lucrative genes. Sequana counters that the islanders, who are English-speaking British subjects, were given detailed forms describing the study, and only people who freely gave informed consent participated.
"They wanted to take part," said Carrie Le Duc, the Sequana scientist who accompanied Zamel to Tristan last fall. "They know what asthma is and they want to be a part of helping other people."
'Everything Had to Work'
The Drakensberg took four days to get within helicopter or barge range of the wave-pummeled island, which has no airstrip or protected harbor. Islanders hoist their fishing boats into dry dock after every trip.
"WELCOME TO THE LONELIEST ISLAND," says a painted wooden sign at the water's edge.
The island's 90 or so families live in lava-rock houses on a grassy ledge in a settlement called Edinburgh. Potato patches fill another ledge two miles away. Cattle and sheep graze.
For the three weeks she was there, Le Duc lived with a young Tristanian couple, there being no public lodging on the island. They gave her what she says is the traditional gift to a newcomer: heavy wool socks. "They bring hospitality to a new level," she said of the islanders.
Le Duc had spent six months getting ready, adapting standard experimental techniques to the island's two-bed, bare-bones unheated hospital. Her portable lab filled five car-size wooden shipping crates: a plexiglass compartment for handling sterile samples, table-top centrifuges, tanks of liquid nitrogen, carboys of chemical reagents, gallons of bleach disinfectant, pipettes, thousands of test tubes and a number of large red plastic bags in which to carry every scrap of lab waste back to Cape Town.
"It was like an expedition to the moon," said Sequana's director of genetics, Jeff Hall. "There was just one chance, and everything had to work."
All told, about 270 of the island's 300 residents participated in the study. Zamel and another Toronto researcher gave the study subjects various clinical asthma tests and took blood samples and family histories. Some also had a skin test for allergies.
Working in the converted maternity room wearing a heavy wool sweater under her white lab coat against the spring chill, Le Duc worked 12-hour days processing blood samples, dividing each sample into four tubes.
She added buffer chemicals to the blood and centrifuged the tubes to separate the red cells, which contain no genetic material, from the sought-after white cells. Then, in the most onerous step, she had to freeze the purified white cells for storage and shipping; but if they froze too quickly, they would burst, making the trip a bust. Using a crank-operated device adapted for the task, she lowered the tubes oh-so-slowly into a fog of liquid nitrogen.
Only months later, after the cells were thawed and tested back in Sequana's La Jolla facility, did she learn that she had succeeded: The cells were intact and alive.
They responded to a standard lab procedure to get them dividing and growing in a test tube, and transformed into what biologists call a cell line. Although the knack of culturing cells has been around for decades, it may still seem amazing that a California lab is home to living tissue derived from hundreds of people on the other side of the world.
By culturing the Tristanians' cells, Sequana has created a virtually unlimited supply of genetic material to analyze. "Even after islanders pass away, we've got their DNA for perpetuity," Hall said.
Searching for Evidence of Genetic Causes
It is not uncommon for researchers to zero in on an insular population for clues to the genetic basis of a disease.
They have sought genetic links to mental illness in the Old Amish of the eastern United States; their extensive intermarrying, well-documented family histories and relative isolation simplify gene searches, though no conclusive links have been found. Researchers have found evidence of a genetic basis of certain forms of diabetes by analyzing the Pima Indians of Arizona, who are especially burdened by the disease.
In perhaps the most famous example, the key to unlocking the Huntington's disease gene was found by studying an isolated Venezuela community that had a high level of the disease.
But the direct involvement of a biotech company in such research is a new twist, and it has aroused concern among groups claiming to be champions of indigenous peoples. The Rural Advancement Foundation International, an Ottawa-based group, has criticized Sequana and other genomics companies for "committing acts of genetic biopiracy and, in the process, violating the fundamental human rights of the people from whom DNA samples are taken."
The foundation is leading a drive to develop international sanctions preventing the patenting of DNA information gleaned from indigenous peoples.
For its part, Sequana says not only that Tristanians are literate people who gave their consent to be studied, but that the company has donated medical equipment for diagnosing asthma to the island hospital. In exchange for their cooperation, the islanders have been promised a lifetime supply of any medication developed as a result of the research, said Sequana's Harris. Still, the company has declined requests to examine the consent forms used on Tristan.
The Tristan project also exemplifies the increasing tension between commercial and academic genomics. At scientific meetings, Sequana-sponsored researchers have said that two "candidate genes" responsible for asthma on Tristan--called "wheeze1" and "wheeze2"--have been identified. But the company has declined to divulge crucial details, such as the chromosomes where the candidates lie.
That irks other government-funded researchers hotly pursuing asthma-susceptibility genes. They worry about "wasting" vast resources duplicating Sequana's efforts when they could be searching different chromosome areas for other candidate genes, said Susan Banks-Schlegel, a cell biologist at the National Heart, Lung and Blood Institute and a member of the Collaborative Study on the Genetics of Asthma, a group of researchers at nine U.S. institutions.
"There's concern in the community that [Sequana] should be more forthright about what's going on," she said.
The company is only protecting its investment, Harris said. "There's always the argument [that] industry is a parasite, [that] we keep everything secret. But we do release as much information as soon as we can."
Henry Greely, a Stanford University law professor and co-director of Stanford's Program in Genomics, Ethics and Society, says that the government-led Human Genome Project "is in some ways being superseded by private research."
Some academics, he said, will be chagrined to find that their gene discovery has already been made--and patented--by a genomics firm. "What bothers some people is the idea that this genome, which would seem to be the property of us all, is being used for profit by some companies."
Despite Advances, the Task is Daunting
To get at sought-after genes, Sequana uses an approach called positional cloning--so called because the aim is to copy, or clone, a desired gene by zeroing in on its location along the chromosome.
Essentially, it involves breaking down all of an individual's DNA; sifting through thousands of DNA fragments for known markers; and comparing the marker patterns of large numbers of related people with and without a hereditary disease. The DNA of people in the same family who have a gene predisposing them to a disease will yield similar marker patterns.
Typical of genetic engineering techniques, positional cloning is easier said than done. But the key is identifying large numbers of close-knit families with well-documented medical histories. Going to Tristan, where all islanders are at least cousins, provided Sequana with something of a shortcut.
Hall had done pioneering work on the breast cancer-susceptibility gene, BRCA1, while on a UC Berkeley fellowship in the early '90s--the old days, before there were any genomics companies. Even he is somewhat startled by how quickly commercial gene hunting has advanced.
Referring to the computerized gene-sequencing machines outside his office door, he said, "An academic lab would be lucky to have one or two of these machines. But we have 35 right here, and another 12 upstairs."
When he was at Berkeley looking for BRCA1, it took the team three years to analyze 400 different DNA markers from 400 people, he said. At Sequana, with its massive "bioinformatics" capability, he estimated that the same job would take about two months.
But that does not mean that finding disease genes is a breeze. "The easy genes have already been cloned," Hall said, referring to those involved in disorders like Huntington's disease, which develops in every person who inherits the singular Huntington's gene.
Asthma's genetic roots are far more difficult to uncover, researchers say, because only 5% to 10% of cases have a clear genetic component. And because the disease takes many different forms, affecting people at various ages and to varying degrees, many genes appear to be involved, researchers say.
On Tristan, Zamel said, most islanders given a skin allergy test were sensitive to dust mites--probably the island's leading asthma trigger, because there are no cats, trees, air pollution or other usual suspects. "They are very sensitive to house dust," he said. "It's not something special that causes asthma on Tristan. When people from there go any place else they have the same asthma."
Decoding DNA, Raising New Questions
Unlike drug and biotech companies that are hoping to develop products to sell, genomics firms are primarily in the information-gathering business.
A few, such as Incyte Pharmaceuticals in Palo Alto and Human Genome Sciences in Rockville, Md., are chemically analyzing human DNA and building computerized DNA libraries without worrying overmuch about the genetic material's actual function. Eventually, the thinking goes, the decoded DNA will be invaluable.
Sequana's tack is more disease-directed, and its asthma research will bring in money whether or not it leads to new diagnostics or drugs. Boehringer Ingelheim, the German drug company, has agreed to pay Sequana up to $30.5 million for exclusive access to findings, and more money will pour in if the drug company ends up marketing a new asthma treatment.
Sequana has deals with other drug companies, too, to hunt for genes involved in osteoporosis, obesity, diabetes and schizophrenia. "We're using genetics to validate targets for drug discovery," Harris said.
Visitors to Sequana's hillside lab--located in an area of La Jolla known to insiders as Biotech Beach--receive a compact disc case customized with their name emblazoned across a DNA model. The gimmick is meant to suggest that day in the future when scientists will have the ability to quickly "read" an individual's DNA sequence, or "genotype" that person, and store all the genetic information on a CD--including information about diseases that may not strike for years.
"There will be an ability someday to genotype somebody," said Sequana's founder and CEO, Kevin Kinsella. "The question is, how will people use that information?"
The hope, of course, is that such information will help people avoid diseases to which their genes predispose them. But Kinsella acknowledges that a comprehensive genetic profile would raise questions about protecting people's privacy and preventing job or insurance discrimination on the basis of their genetic risks.
Then there is the issue of futility, of knowing long in advance that some illness may strike but not being able to do much about it.
Kinsella said he had a great-aunt who died of Alzheimer's, a disease that in many instances has a genetic component, researchers say. "Where has that gene ended up? Would I want to know that? I don't know."
A 'Most Patient People'
At the end of their three-week stay on the island, Zamel, Le Duc and the other Toronto researcher, Patricia McClean, threw a party for the islanders in the island pub. They danced, drank Castle beer and ate deviled eggs, stuffed mutton, little quiches and Tristan potato chips. Curry scented the air, a reminder of the days in the last century when ships plying the spice trade stopped at the island for fresh water.
In a speech, Zamel thanked the islanders for their cooperation in the asthma study and expressed the hope that something would come of it.
"They're the most patient people I've ever known," Le Duc said, "and the only ones who haven't lost the meaning of community. There's no crime on Tristan. Money means nothing to them." She said that as soon as she boarded the barge that took her to the waiting ship, she was crying. "It's a very hard place to leave."
By the year 2005, scientists led by the National Institutes of Health and the Department of Energy expect to decipher all the DNA in a representative set of the roughly 100,000 genes that make up the human genome. That means determining the sequence of human DNA's 3 billion chemical bases--information that would fill 1,000 1,000-page telephone books. What are some of the potential uses--and misuses--of the human genome sequence information when it becomes available?
Daniel J. Kevles, Head, Program in Science, Ethics, and Public Policy, Caltech:
"One of the most important uses of the Human Genome Project will be, of course, the information that it provides that will greatly assist in the understanding, diagnosis, and treatment of disease. Beyond that, the data about our genetic essence should be used to illustrate how much we are the products of the interaction of nurture with nature, that environment counts. And it should be employed to call attention to how closely related we are to the rest of life and to each other."
"The worst way in which sequencing the human genome could be used would be as a pseudo-scientific prop to racism. Sequencing the human genome will undoubtedly show genetic diversity between different ethnic groups, and some may try to twist diversity into a hierarchy in which their own ethnic group comes out on top."
"The best possible use is for the development of treatments for disease.... The ultimate value is to use the genes themselves as treatment, in other words, human gene therapy. There are two major areas of concern. First, ... discrimination in health coverage, insurance rates, job selection, or worse, could occur if the genetic makeup of an individual is allowed to be known and used without the consent of the individual. Second is the future misuse of trying to use the information that goes into a human being to try to 'redesign' humans or make them 'better' by human genetic engineering."
"The information generated by the human genome project, as well as the new technologies that emerge from this endeavor, will ensure the United States a highly competitive position in the worldwide biotechnology industry."
"The Human Genome Project will develop tools to identify the genes involved in both rare and common diseases over the next 15 or 20 years.... Once the molecular basis of a disease is revealed, scientists have a far better chance of defeating it. One approach is to design highly targeted drugs that act on the cause, not merely the symptoms, of disease. Another is to correct or replace the altered gene through gene therapy."
"Overselling of the results of laboratory and clinical studies by investigators and their sponsors--be they academic, federal, or industrial--has led to the mistaken and widespread perception that gene therapy is further developed and more successful than it actually is. Such inaccurate portrayals threaten confidence in the integrity of the field and may ultimately hinder progress toward successful application of gene therapy to human disease."
Researched by TERENCE MONMANEY and TRACY THOMAS / Los Angeles Times
Tracking a Rogue Gene
Inherited genetic errors directly cause 3,000 to 4,000 diseases, such as cystic fibrosis, and play an indirect role in many others, including asthma. Here's one approach that researchers use to zero in on a gene harboring a defect, or mutation, associated with disease:
1. Launch investigation: Studies of extended families or isolated communities in which a disease is very common may show that susceptibility to it is inherited.
2. Gather evidence: After collecting blood samples from many family or community members, scientists extract DNA from the white blood cells, then compare the DNA of afflicted and healthy individuals.
3. Narrow the search: Using genetic "markers," or fragments of DNA that occur at known locations along chromosomes, scientists look for a marker pattern unique to the afflicted people; the disease-causing gene should lie near those markers.
4. Identify a suspect: Hundreds of genes in that chromosome region are analyzed and compared, until a "candidate" gene surfaces. Once the gene is located, the crucial sequence of chemicals along its DNA strand is determined.
5. Build the case: More afflicted people are studied to see if they carry a gene with the same sequence. If so, the gene may be defective.
6. Further testing: Comparing the candidate gene's DNA sequence in afflicted and healthy people reveals the exact difference, or defect. Even if one of the chemical bases is out of order, disease could result.
7. Treat the problem: If many people with the disease have the same gene mutation, a diagnostic test may be possible. Also, by studying the gene's normal function, scientists may develop new treatments--perhaps even gene therapy, an experimental technique where researchers try to endow a patient with a "normal" copy of the gene.
Gene Mapping: Researchers, attempting to find the locations of specific genes on a chromosome, create a map using genetic "markers," which consist of well-defined DNA fragments at known locations.
Chromosomes: Each chromosome contains the DNA for thousands of individual genes.
Human Cell: Each cell in the human body (except red blood cells) contains the genetic information to build a human being.
Cell Nucleus: Inside the nucleus, 6 feet of DNA is packaged into 23 chromosome pairs.
Source: U.S. Department of Health and Human Services
The 300 residents of Tristan da Cunha are thousands of miles from the stress and pollution of urban life, yet half are plagued by asthma.
About This Series
The cloning of a sheep named Dolly sent shockwaves throughout the world this year. But that is only one of a host of advances in biotechnology. The revolution is touching virtually all corners existence, from conception to nutrition to disease control. The genetic engineering advances also raise basic questions about how society will deal with these newfound abilities, who should control their use and how far research should be allowed to proceed.
Sunday: The biotechnology revolution--the future has arrived.
Monday: What is the "self" and can it be cloned?
Tuesday: The U.S. government's reluctance to regulate reproductive technology raises some thorny issues.
Today: The quest to map the human genome leads down some unusual roads.
Thursday: Barnyard biotech--of cows with medicinal milk and pigs with human-like organs.
ON THE WEB: Graphics, photos and stories from "In Our Own Image" are available on the Los Angeles Times World Wide Web site at: http://www.latimes.com/cloning/
Copyright, 1997, Los Angeles Times. Reprinted by permission.