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This Week in PNAS: Feb 10, 2015

In the early, online edition of the Proceedings of the National Academy of Sciences, researchers from the University of Virginia describe an epigenetic mark that appears to affect the way an individual's brain responds to emotional expressions, such as anger and fear. The researchers assessed methylation at the oxytocin receptor gene OXTR in almost 100 Caucasian adults between 18 and 30 years of age who underwent functional magnetic resonance imaging during an emotional face-matching task. Their results pointed to elevated OXTR methylation in those with more pronounced neural responses to emotional faces and apparent shifts in functional ties between the brain's amygdala and other parts of the brain contributing to social and emotional perception.

Researchers from Massachusetts General Hospital,Harvard Medical School, the Broad Institute, and elsewhere introduce a scheme for interpreting heritability patterns based on SNP data from groups of unrelated individuals. The team provided proof-of-principle applications of its statistical method, known as "massively expedited genome-wide heritability analysis," or MEGHA, on several brain features using genome-wide SNP data and brain imaging measurements for 1,320 individuals. The study's authors argue that their results "demonstrate the unique capability of MEGHA for large-scale heritability-based screening and high-dimensional heritability profile construction." 

Finally, a National Institute of Neurological Disorders and Stroke-led team delve into the functional impact of point mutations in the neuroligin genes NLGN3 and NLGN4X, which have been implicated in autism spectrum disease risk. Using a combination of in vitro and in vivo experiments, the team teased apart phosphorylation patterns, protein interactions, and synaptic effects associated with the mutations. In particular, the investigators point to a NLGN4X mutation that seems to interfere with the phosphorylation of the protein it encodes, leading to alterations in associated synaptic activity.