By spring, world may get a first draft of genome
The first draft of the blueprint for the genetic makeup of humans should be completed by spring 2000.In fact, the international effort to sequence the human genome is on schedule, according to Dr. Richard Gibbs of the Baylor College of Medicine. A working draft should be completed early next year, as planned.
Researchers from the 16 centers who are collaborating on the project confirmed that they have enough equipment and staff to provide information about 90 percent of the genome by next spring.
The human genome is the blueprint for the body's genetic code.
The estimated 100,000 genes that make up the genome contain information about how cells reproduce and carry out functions.
This information is stored on 3 billion base pairs, or chemical building blocks, in the molecule known as DNA.
The hope is that by understanding the sequence, researchers will learn how disease occurs and be able to treat and even prevent it. So far 739 million base pairs (about one-fourth of the human genome) have been sequenced and the information released into the public domain so it can be accessed without fees, patents, licenses or other limitations. The sequence of several chromosomes are nearing completion, as well.
The consortium of researchers completing the project include researchers from the United States, the United Kingdom, France, Germany, Japan and China. The final sequence should be available in 2003.
Genetic therapy may get boost from new study
A Purdue University researcher studying genetic on-off switches in yeast found a system that could be useful in human gene therapy.
Gunter Kohlhaw, a recently retired Purdue biochemistry professor, envisions a time when gene therapy will alleviate suffering from diabetes mellitus, familial gout, hypercholesterolemia or any of the other 400-plus diseases caused by an underlying genetic deficiency. But in many cases, before gene therapy can work efficiently, doctors must find genetic switches to turn therapeutic genes on and off. Such switches let them regulate levels of compounds like insulin in diabetics.
Kohlhaw and his co-workers have found one switch that looks promising.
"We have a system that is in its infancy but which conceivably could be useful in mammals," Kohlhaw says. "We know it works perfectly in cultured mouse cells."
Other on-off gene switches already exist, but they depend on hormones or the antibiotic tetracycline. People have to eat or get an injection of a hormone or antibiotic to turn the therapeutic genes on or off, and some people can't or don't want to risk side effects associated with those compounds.
Because the compounds that make up Kohlhaw's gene switch are natural components of yeast, they shouldn't affect human health, he says, although researchers need to test them to be sure. Both compounds are part of the yeast's system for producing leucine, an amino acid essential to human health.
"What's really unique about the system is that it's not present in humans, so it can be genetically engineered in human cells and completely controlled from the outside," says Michael Hampsey, a professor in the Department of Biochemistry at the University of Medicine and Dentistry of New Jersey.
If further research shows that the genetic dimmer switch works as well in humans as in mouse cells and if isopropylmalate is indeed nontoxic, people with diabetes, for example, might control their insulin levels by eating the right amounts of isopropylmalate, Kohlhaw says.
Researchers at UCLA's Jonsson Cancer Center hope to find long-term adult cancer survivors for a unique study to learn about the physical and psychological effects of cancer long after diagnosis and treatment.
The study is funded by a grant from the National Cancer Institute and participants will be asked to take part in a confidential, hour-long interview. The researchers are looking for survivors of invasive breast, colorectal or prostate cancers, as well as Hodgkin's or non-Jodgkin's lymphomas who are at least five years out from the initial diagnosis.
Results of the study will held design a new method to assess quality of life for long-term cancer survivors.
UCLA's Jonsson Cancer Center is the only institution nationwide researching how cancer affects long-term survivors differently at different stages of life.
In addition to those interviewed in person, a second phase of the study will include hundreds more long-term cancer survivors, who will receive a survey by mail. The results of the first phase study will be available by summer of the year 2000.
Long-term survivors who participate in the in-person interviews will receive $20 for their time. Leedham said the study seeks both the positive and negative effects that cancer can have on patients' lives.
For more information on the Jonsson Cancer Center study, or to volunteer to take part, call (310) 794-9237.