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This Week in PNAS: Apr 30, 2013

In the early, online version of the Proceedings of the National Academy of Sciences, a group from Germany and the US looks at whether post-traumatic stress disorder stemming from childhood events coincides with distinct gene expression and epigenetic profiles in individuals' blood samples. When they compared array-based gene expression and DNA methylation patterns in samples from 61 individuals with PTSD, the investigators found different expression patterns in those who had experienced childhood abuse relative to those who had not — changes that often corresponded to methylation shifts in the childhood trauma group. Expression signatures differed yet again when the team considered blood samples from 108 individuals with a traumatic past but no signs of PTSD.

The transcription factor-coding gene MYBL1 is prone to recurrent, truncating rearrangements in at least one diffuse pediatric low-grade glioma sub-category, according to another study in PNAS. Researchers from the Dana-Farber Cancer Institute and elsewhere performed copy number analyses on 44 formalin-fixed, paraffin-embedded samples, representing tumors from several histologically defined diffuse pediatric low-grade glioma sub-categories. Together with whole-genome sequencing on a tumor from the diffuse astrocytoma grade II, or DA2, sub-category, the copy number data pointed to a key alteration in the DA2 tumors: a partial duplication of MYBL1 and truncation of the gene's regulatory domain-coding sequence. The team also saw two tumors in another histological sub-group that harbored truncations to a related gene — MYB — hinting at a role for the transcription factor family in low-grade glioma risk.

An international team led by investigators in the US and Australia describes a high-throughput array for finding stretches of the wheat genome under selection during crop improvement. After selecting target SNPs from transcriptome sequence data on more than two-dozen wheat accessions, the researchers used this chip to put together a genetic diversity map representing nearly 3,000 wheat accessions. Their data highlighted sites of differentiation between populations, for instance, as well as regions of the genome that have undergone selective sweeps as part of the crop improvement processes. For more on this study, check out a related news story in our sister publication GenomeWeb Daily News.