DNA Sequencing Completed for African Man and Asian Man

November 07, 2008 10:58 AM
by findingDulcinea Staff
The findings provide insight into the genetic makeup of non-European races, and may usher in a new era of individualized medical care based on genetics.

Scientists Herald New Gene Maps

Two separate teams of scientists published their findings in the science journal Nature, reporting that gene maps have been completed on a Chinese man and a West African man using faster and cheaper technology.

The two anonymous subjects, one of Han Chinese descent and the other an ethnic Yoruba man from Ibadan, Nigeria, are the first people of non-European descent to be fully mapped. The only other men who have ever been sequenced are Nobel laureate James Watson, who discovered the DNA double helix, and genomics pioneer J. Craig Venter, both of European descent.

The findings are a significant advance toward personalized medical care based on knowledge of an individual’s genetic makeup, some scientists say.

“We’re getting a little glimpse of what will happen over the next couple of years,” said geneticist Dr. James R. Lupski, of Baylor College of Medicine.

Genetic information allows scientists to better understand humans from an evolutionary and disease standpoint, Lupski said. While scientists say that humans are more than 99 percent identical, “the remaining tiny fraction of genes make each person distinct and can help explain individual differences in susceptibility to disease and physical responses to the world,” reports U.S. News & World Report.

The two new genomes were completed using Illumina technology that makes use of a sequencing-by-synthesis method that is much faster and cheaper than the old tools used in the Human Genome Project, reports Wired. While the first human genome completed in 2004 cost hundreds of millions of dollars, the study on the Chinese man cost only $500,000.

“With such rapid advances in next-generation technologies, and with ‘third generation’ technologies emerging, this is just the beginning of the era of the individual genome,” wrote geneticists Samuel Levy and Robert Strausberg of J. Craig Venter Institute, in Nature. “Soon, association studies using complete individual genomes will become the approach of choice for understanding the complexity of human biology and disease.”

But some scientists caution that it will still be some time before they figure out how to use the genetic data currently available to make advances in medical care.

“We are at a stage where technology is outpacing our biological understanding,” said Charles Lee, director of cytogenetics at the Harvard Cancer Center, to U.S. News & World Report. “We have massive amounts of genetic information being generated, but a limited understanding of what this data means to the individual. There is still a long way to go before we can accurately interpret much of the data that we are generating.”

Opinion & Analysis: ‘The last of the single human genome papers?’

ScienceBlogs comments that the studies mark a “potential historical milestone: quite possibly the last two papers ever to be published in a major journal describing the sequencing of single human genomes from healthy individuals.” The four individuals mappings that have already been done have provided us with sufficient information about the human genome, and future mappings are likely to provide little new information. Scientists are now tasked with analyzing the sequences already mapped. “Human genetics now moves into a phase of new challenges and rewards—the era of population genomics.” It also says that while the Illumina technology used allowed the researchers to conduct their studies faster and more inexpensively than the old Sanger chemistry, “many technical challenges still remain.”

Reference: Studies of Asian, African man

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