Greater Variation Seen in Human Genome

Nov. 22, 2006 -- The human genome -- our DNA -- may be more complex than scientists previously thought, with greater ethnic divergence.

In a new study published in Nature, researchers report there are fairly large variations between four ethnic groups in 12% of the genome.

The findings may affect research on the genetics of disease, according to the 43 researchers from around the world who worked on the project.

The researchers included Matthew Hurles, PhD, of the Wellcome Trust Sanger Institute in Cambridge, England and Stephen Scherer, PhD, of Canada's University of Toronto and Toronto's Hospital for Sick Children.

Study Results

The scientists studied the DNA of 270 people from African, European, Japanese, or Chinese ancestry in four locations: Nigeria, Utah, Japan, and China.

They found 1,447 DNA regions that were either duplicated or deleted among the various ethnic groups.

Previous DNA maps had flagged smaller DNA variations. The new map shows those small differences may just be the tip of the iceberg.

In short, based on this study, the DNA mix is more intricate than expected.

Unique Patterns

"Each one of us has a unique pattern of gains and losses of complete sections of DNA," Hurles says in a Wellcome Trust Sanger Institute news release.

"We now appreciate the immense contribution of this phenomenon to genetic differences between individuals," he adds.

"We used to think that if you had big changes like this, then they must be involved in disease," Scherer says in a news release.

"But we are showing that we can all have these changes," Scherer says.

Journal editorialists write "the stage is set for global studies to explore anew ? the clinical significance of human variation."

Editorialists are Kevin Shianna, PhD, and Huntington Willard, PhD, of Duke University's Institute for Genome Sciences and Policy.

SOURCES: Redon, R. Nature, Nov. 23, 2006; vol 44: pp 444-454. Shianna, K. Nature, Nov. 3, 2006; vol 444: pp 428-429. News release, Wellcome Trust Sanger Institute. News release, Howard Hughes Medical Institute.