Genetic Copy Variations and Disease
From the June 2009 Scientific American Magazine | 0 comments
Genetic Copy Variations and Disease
A new sense for how variable numbers of genes cause disease
By Melinda Wenner
Scientists published the first draft of the human genome nearly a decade ago, but the hunt for disease genes is far from over. Most researchers have focused on single changes in DNA base pairs (AT and CG) that cause fatal diseases, such as cystic fibrosis. Such mutations among the genome’s three billion base pairs don’t tell the whole story, however. Recently geneticists have taken a closer look at a genetic aberration previously considered rare: copy number variation (CNV). The genes may be perfectly normal, yet there is a shortage or surplus of DNA sequences that may play a role in diseases that defy straightforward genetic patterns, such as autism, schizophrenia and Crohn’s disease, the causes of which have stumped researchers for decades.
American geneticist Calvin Bridges discovered copy number variation in 1936, when he noticed that flies that inherit a duplicate copy of a gene called Bar develop very small eyes. Two decades later a French researcher studying human chromosomes under a microscope identified CNV as the cause of Down syndrome: sufferers inherit an extra copy of chromosome 21. By all appearances, CNV was rare and always a direct cause of disease....
Note: This article was originally published with the title, "Too Little, Too Much".
ABOUT THE AUTHOR(S)
Melinda Wenner, based in New York City, described in the May issue how "quorum-sensing" bacteria could help beat antibiotic-resistant germs.
Genetic Copy Variations and Disease
A new sense for how variable numbers of genes cause disease
By Melinda Wenner
Scientists published the first draft of the human genome nearly a decade ago, but the hunt for disease genes is far from over. Most researchers have focused on single changes in DNA base pairs (AT and CG) that cause fatal diseases, such as cystic fibrosis. Such mutations among the genome’s three billion base pairs don’t tell the whole story, however. Recently geneticists have taken a closer look at a genetic aberration previously considered rare: copy number variation (CNV). The genes may be perfectly normal, yet there is a shortage or surplus of DNA sequences that may play a role in diseases that defy straightforward genetic patterns, such as autism, schizophrenia and Crohn’s disease, the causes of which have stumped researchers for decades.
American geneticist Calvin Bridges discovered copy number variation in 1936, when he noticed that flies that inherit a duplicate copy of a gene called Bar develop very small eyes. Two decades later a French researcher studying human chromosomes under a microscope identified CNV as the cause of Down syndrome: sufferers inherit an extra copy of chromosome 21. By all appearances, CNV was rare and always a direct cause of disease....
Note: This article was originally published with the title, "Too Little, Too Much".
ABOUT THE AUTHOR(S)
Melinda Wenner, based in New York City, described in the May issue how "quorum-sensing" bacteria could help beat antibiotic-resistant germs.
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