Study adds nearly 10% to knowledge of human genetic variation

A whole-genome analysis of three groups of the world’s most genetically diverse people provided an astonishing 3 million new single-nucleotide polymorphisms (SNPs) to the approximately 13 million currently catalogued in publicly accessible databases. The research team, led by Sarah Tishkoff of the University of Pennsylvania, sequenced the genomes of 15 Africans belonging to three distinct groups (Pygmy, Sandawe, and Hadza) that still maintain a hunter–gatherer lifestyle. The sequencing and subsequent statistical analysis provided researchers with a rich expansion in variants, most of which occurred in noncoding sequences. The findings, featured on the cover of the 3 August issue of Cell, also suggest that modern humans contain sequences acquired through breeding with a now-extinct early hominid in Africa hundreds of thousands of years ago. As expected, the African genomes contained no traces of Neanderthal DNA. The extent of SNP variation suggests that there remain many more population-specific differences to be catalogued, and that those variations could have important health implications. For instance, although only about 72,000 of the new variants were in coding regions, highly divergent sequences appeared in genes involved in smell and taste as well as immune system–related and growth hormone genes, suggesting that these loci evolved in response to diet, climate and local pathogens. We can expect high-coverage, whole-genome sequencing to reveal more surprises in human evolutionary history, as more ethnically diverse genome data sets are integrated with studies of human health. —Karyn Hede, News Editor

A significant step forward in the DTC genomics world

23andMe, arguably the industry leader in the world of direct-to-consumer (DTC) genetic testing, recently announced that it is seeking approval from the US Food and Drug Administration (FDA) for an initial set of seven health-related tests.

I have been a personal critic of the DTC industry in the past. My major concerns have been that interpretation of risk scores for common diseases is unreliable, the claims made by these companies are often exaggerated, and the medical utility of such testing has been questionable. However, the landscape is now changing. As Evans and Berg point out in a recent commentary (JAMA 2012;306:2376–2377), once whole-genome and whole-exome sequencing are available directly to consumers, it will have effectively transitioned to the status of a full-fledged traditional medical test. Now that such testing is migrating from casual entertainment to a source of real medical information, with the power to help, harm, or confuse (as with any medical test), appropriate regulation is warranted.

23andMe should be commended for stepping up to the plate and opening a dialogue with the FDA to move toward sensible regulation of such testing. This will help satisfy critics and, more importantly, serve to increase the legitimacy of such offerings. Crafting appropriate regulation will not be easy. Any regulation of medical testing must navigate a fine line between excessive paternalism on one hand and allowing overly casual (and thus harmful) use on the other. But the only way to ultimately realize this balance is by starting a dialogue. —James P. Evans, Editor-in-Chief

Genetics in Medicine Mission Statement

Genetics in Medicine is a monthly journal committed to the timely publication of:

  • Original reports which enhance the knowledge and practice of medical genetics

  • Strategies and innovative approaches to the education of medical providers at all levels in the realm of genetics

As the official journal of the American College of Medical Genetics and Genomics (ACMG), the journal will:

  • Provide a forum for discussion, debate and innovation concerning the changing and expanding role of medical genetics within the broader context of medicine

  • Fulfill our responsibility to the College membership through the publication of guidelines, policy statements and other information that enhances the practice and understanding of medical genetics

Finally, as genetics becomes increasingly important in the wider medical arena, we will be an accessible and authoritative resource for the dissemination of medical genetic knowledge to providers outside of the genetics community through appropriate reviews, discussions, recommendations and guidelines.