human variation revealed...,

The Scientist | Scientists have generated the most comprehensive map of the structural variation that exists among normal, healthy humans, according to a study published online today in Nature. Understanding normal variation between individuals is critical to identifying abnormal changes that may contribute to a wide variety of heritable diseases.

"I think it's considered to be a landmark paper," said geneticist Frank Speleman of the Center for Medical Genetics at Ghent University Hospital in Belgium, who was not involved in the work. "It's quite important in the complete context of genome wide association studies and genetic predisposition."

Using microarrays that contained more than 42 million probes, genome scientist Stephen Scherer of The Hospital for Sick Children in Toronto and the University of Toronto and his colleagues searched the genome of 40 healthy individuals for copy number variants (CNVs) -- areas of the genome that come in varying quantities as a result of deletions, insertions, or duplications. The researchers identified 11,700 CNVs 443 base pairs or greater in size, with an average of approximately 1,000 CNVs differing between any two individuals. "[That's] an important amount of normal variation that happens in the genome," Speleman said.