Analysis of Human Genome Map Yields Surprises
Humans have a "surprisingly small" number of genes -- about twice the number as a worm or a fly -- and hundreds of those genes remain from bacteria that "infected human predecessors millions of years ago and left their microbial DNA behind," according to the first "detailed" analysis of the human genome. The Washington Post reports that scientists will release the results of studies today at a Washington news conference, which will appear live on the Internet, while the journals Science and Nature will publish a "thick collection" of more than 12 landmark articles this week. According to preliminary reports that appeared in a British newspaper Sunday, only 23 chromosomes "directly" function to reproduce human life, "tak[ing] up less than one inch of the six-foot-long strand that's stuffed inside virtually every cell in the body." The genome -- filled with "weird life-like entities" that have "settled ... like squatters" -- has proven "far more than a mere sequence of biological code written on a twisted strand of DNA," and is instead a "dynamic and vibrant ecosystem of its own," invoking images of the "thriving world of tiny Whos that Dr. Seuss's elephant Horton discovered on a speck of dust," the Post reports (Weiss, Washington Post, 2/11). "We suddenly have the global view, the view of the earth from the moon, and it's pretty thrilling," Dr. Harold Varmus, former NIH director and head of the Memorial Sloan-Kettering Cancer Center in New York, said of the studies (MSNBC.com, 2/10). "It's as though we have climbed to the top of the Himalayas. We can, for the first time, see the breathtaking vista of the human genome," Eric Lander, director of the Whitehead Institute Center for Genome Research in Cambridge, Mass., added (Stroh, Baltimore Sun, 2/11).
According to scientists, humans have about 30,000 genes, only five times as many as baker's yeast, and far less than the 80,000 to 120,000 previously estimated (Washington Post, 2/11). "If you're judging the complexity of an organism by the number of genes it has, we've just taken a hit in the pride department," Dr. Francis Collins, head of the publicly funded Human Genome Project and director of the National Genome Research Institute, said (Sternberg, USA Today, 2/12). However, researchers reported that the genes produce about 30,000 products, mainly proteins, which get "cut into pieces" and "shuffled," and then "pasted" into "novel arrangements," allowing a single gene to produce 10 or more proteins -- while simpler organisms' genes produce only one or two proteins each (Washington Post, 2/11). The studies also revealed that humans share 99.99% of the same DNA with each other, confirming that "there is no basis for the scientific concept of race." Dr. Craig Venter, head of Celera Genomics Corp., the privately funded group that mapped the human genome, explained, "You and I differ by 2.1 million genetic letters from each other," adding, "which means we all are essentially identical twins." (BBC News, 2/11). The findings could help "temper cultural biases about the genetics of race." However, the studies also indicate that sperm cells carry twice as many mutations as egg cells, suggesting that men serve as the "major source" of genetic errors and "evolutionary innovation" -- results that will likely "fan the flame of gender wars." In addition, researchers found that some of the so-called "junk" DNA scattered throughout the human genome, which scientists had thought was useless "genetic detritus," may "pla[y] an important role" in how people function, such as by helping humans deal with stress (Washington Post, 2/11).
Amid the "hoopla" surrounding the recent studies, scientists hope to "develop new wonder drugs or therapies" to treat individual patients with ailments such as cancer and Alzheimer's disease (Stroh, Baltimore Sun, 2/12). "It's going to revolutionize science and medicine," Tim Hubbard of the Sanger Center in Britain said, adding, "We're going to provide doctors with much more powerful tools to diagnose exactly what is wrong with somebody" (MSNBC.com, 2/10). "We go in a hundred different directions at once now," Collins added (Neus, Chicago Sun-Times, 2/12). Researchers contend that the human genome map will allow them to develop "tailor-made" therapies and screen newborns for treatable genetic diseases (Recer, AP/Contra Costa Times, 2/11). The Washington Post reports that scientists have already "discovered many new genes that look like promising targets for drugs," including some related to asthma and Alzheimer's disease (Weiss, Washington Post, 2/11). In addition, scientists hope that the genome map will "revolutionize" psychology and psychiatry, allowing them to tailor drugs for individual patients, rather than using the "current one-size-for-all" pharmaceuticals. "The sequencing of the human genome will improve our ability to identify genetic risk factor genes for a variety of conditions, from addiction to criminality to antisocial personality," Dr. Eric Nestler of the University of Texas' Southwest Medical Center in Dallas said (Recer, AP/Contra Costa Times, 2/11).
But the human genome map also "opens a ... new frontier for potential discrimination." Experts worry that employers and insurers could use genetic information -- such as an individual's lifetime risk of cancer, heart attack and other diseases -- to discriminate against giving an individual a promotion or health insurance. According to the AP/Philadelphia Inquirer, employers and insurers could "save millions of dollars" by using "predictive genetics" to reject those "predisposed" to developing chronic diseases. An American Management Association survey of 2,133 employers this year found that seven are using genetic testing for either job applicants or employees, according to Science. "There has been widespread fear that an individual's genetic information will be used against" him or her, Sen. Bill Frist (R-Tenn.) said, adding, "If we truly wish to improve quality of health care, we must begin taking steps to eliminate patients' fears." Many argue that stopping potential genetic discrimination will require legislation. To combat the problem, Frist and Sen. Olympia Snowe (R-Maine) plan to introduce legislation that would prevent insurance companies from requiring genetic testing and ban the use of genetic information to deny coverage or to set rates. Writing in Science, Sens. James Jeffords (R-Vt.) and Tom Daschle (D-S.D.) said that they favored "legislation prohibiting genetic discrimination." They said, "Misuse of genetic information could create a new underclass: the genetically less fortunate" (Recer, AP/Philadelphia Inquirer, 2/12).This is part of the California Healthline Daily Edition, a summary of health policy coverage from major news organizations. Sign up for an email subscription.