Rare Genetic Variations Are Not That Rare After All

University of California in Los Angeles (UCLA) investigators have recently finished conducting a large-scale genetic survey of the population. Their work led to several interesting conclusions, including the fact that thought-to-be-rare genetic variations are not that uncommon after all.

Details of their study appear in the May 17 online issue of the top journal Science. Team members believe that this work could be used to provide additional information about the nature and genetic origin of multiple human diseases, potentially opening the way to new avenues of research and treatment.

The work was focused on studying 202 genes, in a sample of 14,002 individuals. In other words, the team studied 864,000 out of the 3 billion base pairs in the genome, a relatively small percentage.

On the other hand, this is one of the largest population samples ever analyzed in a genetic study. The senior author of the research was UCLA assistant professor of ecology and evolutionary biology, and of bioinformatics, John Novembre.

“I knew there would be rare variation but had no idea there would be so much of it. Our results suggest there are many, many places in the genome where one individual, or a few individuals, have something different,” the expert says.

“Overall, it is surprisingly common that there is a rare variant in the population. This study doesn't tell us how to cure a particular disease but suggests that disease in general may be caused by rare variants, and if you're trying to find the genetic basis of disease, it's important to focus on those variants,” he adds.

Novembre suggests that an in-depth analysis of genetic variations may be used to provide additional insight into how various conditions work in the human body. Once a disorder is properly understood, new drugs and therapies can be developed to address it.

He adds that the team found one genetic variant every 17 bases, an extremely high rate over what scientists were expecting to find. In the study group, 3,381 people were healthy, while 10,621 suffered from schizophrenia, Alzheimer's, osteoarthritis, multiple sclerosis, bipolar disorder or coronary artery disease.

“The large sample size allows us to see patterns with more clarity than ever before. If rare variants are like distant stars, this kind of large sample size is like having the Hubble Telescope; it's allowing us to see more than before,” Novembre concludes.