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This Week in PNAS: Dec 8, 2015

Editor's Note: Some of the articles described below are not yet available at the PNAS site, but they are scheduled to be posted some time this week.

In the early, online edition of the Proceedings of the National Academy of Sciences, German researchers describe a strategy for focusing in on so-called heterotic patterns associated with enhanced yield traits in hybrid wheat. The team tested its three-stage, quantitative genetics-based computational approach for finding these heterotic patterns in a set of more than 1,600 hybrid wheat plants and 135 Central Europe-adapted winter wheat parental lines. With the help of array-based SNP profiling and information on grain yield in various environments, the study's authors found that the method compared favorably with other methods designed to predict hybrid performance and uncover related heterotic groups. "Wheat has been successfully used for the proof of principle represented here," they write, "but the developed quantitative genetic framework is generically applicable to other self-fertilizing crops as well."

A team from the US and Australia presents a scheme for staunching liver fibrosis for another PNAS study. Based on prior research pointing to a role for the BRD4 in the epigenetic regulation of gene expression patterns related to fibrotic processes, the researchers used chromatin immunoprecipitation plus sequencing to profile the genome-wide distribution of BRD4, along with a histone mark denoting active enhancers. Along with mouse model and cell line studies — including experiments aimed at gauging gene expression consequences of inhibiting various BRD4 domains — results from the ChIP-seq analysis suggest BRD4 enhancer activity contributes to pro-fibrotic expression activity that can be headed off using a bromodomain inhibiting compound called JQ1.

Finally, researchers from Germany, France, the UK, and Austria present findings from a single-cell RNA sequencing study focused on unraveling gene expression patterns at play during fetal brain development. In particular, the team compared transcriptional patterns in hundreds of individual cells from fetal neocortex samples and from three-dimensional cultures of cerebral organoids developed from pluripotent stem cell-derived cerebral tissue. For the most part, the authors found that the cerebral organoid cells "use gene expression programs remarkably similar to those of the fetal tissue to organize into cerebral cortex-like regions," though their findings also highlighted genetic features that were less successfully recapitulated in the in vivo model of human cortex development.