BERKELEY, Calif. – The relatively low cost of sequencing the genome of a Chinese man and an African man brings ever closer the prospect that average people can see their full genetic blueprint, according to separate studies published this week in the journal Nature.

“You will have your genome sequenced, and I will have my genome sequenced,” predicted Rasmus Nielsen, an associate professor of biology at University of California Berkeley, who was a co-author of the Chinese genome study.

The plummeting costs of genome sequencing means an individual’s genetic data will likely be used far sooner than expected to assess disease susceptibility, or to tailor more effective drug regimes.

Nielsen and UC Berkeley colleagues Ines Hellmann and John Pool are the only U.S.-based authors of the article. The other collaborators were scientists from the Beijing Genomics Institute and other Chinese institutions, as well as British researchers.

“No one predicted the price would go down so fast that the sequencing of genomes for medical purposes would happen in my lifetime,” Nielsen stressed.

The two genomes sequenced thus far and made publicly available – those of genetics luminaries James Watson and Craig Venter – cost hundreds of millions of dollars each using an older technology, Nielsen said.

In contrast, it cost less than $500,000 to decode the Chinese male’s genetic blueprint, he said. The team of scientists decoding the African man’s sequence described the endeavor as “low cost.” Both used a technique called “next-generation sequencing” that’s far less laborious and time consuming than the older technique.

“In a few years, you can do it for a few thousand,” Nielsen said. In the coming decades he estimated human genome sequencing costs will drop to “a few hundred dollars.”

Genetic information on the healthy, anonymous males – one a Han Chinese and the other a member of the Yoruba ethnic group in Nigeria – also adds crucial information on genetic diversity among humans.

This latest effort to sequence non-Europeans joins a separate international initiative, announced in September, to sequence 100 Arab human genomes.

Genetic differences between humans have little to do with race, scientists have learned. Humans are more than 99 percent identical at the genetic level, according to the National Institutes of Health.

But that less than one percent variation explains, among other traits, differing susceptibilities to disease, drugs and external factors like pollutants.

Researchers say it’s the nitty-gritty of those variations that will yield invaluable insights into the origins of diseases. The knowledge will also aid in understanding why some people react adversely to drugs or don’t gain any benefit at all, while others respond as promised by drug manufacturers.

“The utility of this is enormous,” Nielsen said.

Sitting in his fourth-floor office at UC Berkeley, Nielsen pointed to a chart listing the Asian male’s genes of concern. While the man’s risk of developing hypertension or diabetes appeared low, he does carry 57 percent of the 16 gene variations known to increase Alzheimer’s disease risk, and 63 percent of the genes linked to tobacco addiction. The Asian man is a heavy smoker, the study noted.

Armed with such knowledge, people can take steps to reduce their odds of developing a disease through lifestyle changes.

What also excites researchers is the promise of increasing the effectiveness of the current crop of pharmaceutical drugs, in addition to spurring drug development for targeting specific gene variations, said Lisa Brooks, program director of the National Institutes of Health’s Genetic Variation Program.

For example, Brooks said, some asthma patients may not respond to a certain drug because they carry a gene variety that produces high levels of an enzyme that reduces the drug’s efficacy.

But someone carrying the analogous gene that’s programmed to produce less of the enzyme will benefit from the drug. So a doctor could change the dosing of the drug to compensate for the extra enzyme, or try another medicine. For now, there’s only nascent understanding of how to use this growing knowledge of genetic diversity and its links to disease inside the doctor’s office. But numerous research endeavors in “pharmacogenomics” and other areas are anticipated to fill the gap in coming decades.

And to keep expanding the list of the small but significant gene variations among individuals for use in medical and other research, the National Institutes of Health earlier this year launched the “1,000 Genomes Project,” in conjunction with an international consortium. The project aims to use next-generation sequencing to produce 1,000 genomes from around the world by 2011, said Brooks, who manages the project.

“I like to say I live in the future,” Brooks commented.

—

(c) 2008, Contra Costa Times (Walnut Creek, Calif.).

Visit the Contra Costa Times on the Web at http://www.cctimes.com/

Distributed by McClatchy-Tribune Information Services.

AP-NY-11-07-08 1355EST