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This Week in PNAS: Dec 30, 2009

In the early edition of PNAS this week, Sarah Tishkoff, Carlos Bustamante, and their team examined population structure and ancestry patterns in West African and African American populations. The researchers incorporated new and old genotyping data to look at genetic patterns in a dozen African populations and 365 African Americans. In the African populations, language and geography usually corresponded to genetic patterns. Meanwhile, their ancestry analyses showed that the amount of West African ancestry varied from about one percent to 99 percent in the African Americans tested — leading the researchers to urge caution in interpreting pharmacogenetic research in this population. A related news story appeared in our sister publication GenomeWeb Daily News.

Albert Einstein College of Medicine researcher Yousin Suh and colleagues reported on genetic variants linked to the activity of the enzyme telomerase in long-lived Ashkenazi Jewish individuals and their children. The researchers found variants in the genes hTERT and hTERC in individuals living to be more than 100 years old and their children. Those with favorable variants had longer telomeres than unrelated individuals, less age-related disease, better cognition, and other signs of healthy aging. "[V]ariations in human telomerase gene[s] that are associated with better maintenance of telomerase length may confer healthy aging and exceptional longevity in humans," the team writes.

Meanwhile, National Institutes of Health infectious disease and immunogenetics researcher Francesco Marincola and his team examined the genetics underlying disparate responses to interferon alpha treatment for hepatitis C virus in African Americans compared with Americans of European descent. The team did not find significant differences in global transcription, SNP, and other patterns related to interferon alpha signaling in healthy African Americans and European Americans, leading them to conclude that differences in treatment outcomes are likely a consequence of population-specific differences in HCV response rather than response to interferon alpha itself.

Researchers from Norway, Spain, and the UK found highly conserved non-coding elements in linkage disequilibrium with non-coding SNPs previously implicated in type 2 diabetes and obesity. When they looked more carefully at these regions, the team discovered that the elements overlapped with areas regulating HHEX, SOX4, and IRX3 — transcription factor genes that seem to contribute to pancreas function in animal models.