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About SickKids

October 7, 2009

Fold up the genetic “roadmap”: SickKids researchers unveil “GPS” to navigate human genome

TORONTO – Exploring the vast landscape of the human genome has been crucial in the understanding of human diseases. Scientists at The Hospital for Sick Children (SickKids) and an international research team have made a major scientific advancement in the study of the genome. The researchers have developed the most comprehensive map yet of genetic variation. The study is published in the Oct. 7 advance online edition of Nature.

Genes are usually present in two copies in a genome; one copy is inherited from each parent. However, some regions can be duplicated or deleted in a phenomenon known as copy number variation (CNV)

In this latest breakthrough, the scientists developed a 3-D map that is expected to help clinicians and researchers navigate through the genome, assisting in the rapidly-evolving field of personalized medicine. (Evolution of Genetic Mapping).

Differences in our DNA sequence contribute to our uniqueness. This variability in our genetic make-up influences most traits, including susceptibility to disease. The researchers estimate they have discovered about 80 per cent of common CNVs in worldwide populations. Thirty places in the genome that could be responsible for susceptibility to certain diseases were identified.

“The scale of this current project is 100 times the scale of all others,” says Dr. Stephen Scherer, co-principal investigator of the study, Director of The Centre for Applied Genomics at SickKids and Professor in the Department of Molecular Genetics at the University of Toronto. “Previous work in this field would be like a paper fold-up map; this advancement is like a GPS that takes you where you need to go. It allows you to navigate the landscape of the genome, from its peaks where there is vast genetic variation, to its valleys devoid of it.”

In 2004, Scherer’s team made headlines with Dr. Charles Lee's Harvard group, when they discovered that copy number variation was a significant form of genetic variation. In 2006, the research teams, along with scientists at the Wellcome Trust Sanger Institute, generated the first CNV map of the genome. This revolutionized the way scientists viewed evolution and disease.

In the current study, the scientists mapped 75 “jumping genes”, which are dynamic regions of the genome found in more than one location. All the data are stored in the Database of Genomic Variants (known as the Toronto database) the premier worldwide source for CNV information.

The researchers also identified areas referred to as “deserts” of DNA variation, where they found few or no CNVs. This suggests that genetic stability in these regions is essential to health or survival.

“Variation is indeed the spice of life and we now know that nature buffers this variation by using CNVs. We are harnessing this knowledge to fight disease,” says Scherer.

The Canadian research was supported by the Canada Foundation for Innovation and Ontario Innovation Trust, Canadian Institutes of Health Research, Genome Canada/Ontario Genomics Institute, the McLaughlin Centre for Molecular Medicine, Ontario Ministry of Research and Innovation, the Wellcome Trust and SickKids Foundation.

The Hospital for Sick Children (SickKids), affiliated with the University of Toronto, is Canada’s most research-intensive hospital and the largest centre dedicated to improving children’s health in the country. As innovators in child health, SickKids improves the health of children by integrating care, research and teaching. Our mission is to provide the best in complex and specialized care by creating scientific and clinical advancements, sharing our knowledge and expertise and championing the development of an accessible, comprehensive and sustainable child health system. For more information, please visit www.sickkids.ca. SickKids is committed to healthier children for a better world.

For more information, please contact:

Matet Nebres
The Hospital for Sick Children
Phone: 416-813-6380
email: matet.nebres@sickkids.ca

Suzanne Gold
The Hospital for Sick Children
Phone: 416-813-7654 ext. 2059
email: suzanne.gold@sickkids.ca