In early online publication in Nature this week, I. Sadaf Farooqi at the University of Cambridge and the Sanger Institute's Matt Hurles are senior authors on work that found large, rare deletions associated with early-onset obesity. Looking at 300 Caucasian patients and almost 7,400 controls, they found both overlapping and de novo deletions on chromosome 16p11.2, and that "all 16p11.2 deletions encompass several genes but include SH2B1, which is known to be involved in leptin and insulin signaling," they write in the abstract.

A paper in this week's issue investigates how left-right asymmetry occurs at an early developmental stage. Using the gastropod Lymnaea stagnalis as a model to study shell coiling, Reiko Kuroda at the University of Tokyo led work that showed that by physically manipulating the orientation of cells in an early embryo — only the eight-cell stage, not the two or four — they could change the left-right asymmetry of the shell and body. These new embryos grew to normal, healthy adults, but their shape was opposite to the mothers' genetic program, which encodes for chirality of offspring. "Moreover, manipulation reversed the embryonic nodal expression patterns," they say, proving that the chiral blastomere arrangement at the eight-cell stage "determines the left-right asymmetry throughout the developmental program, and acts upstream of the Nodal signaling pathway." A News and Views story offers insight.

Structural biology work from scientists at the Vollum Institute of Oregon Health and Science University has revealed the first X-ray crystal structure of a full-length glutamate receptor, a molecule that plays an important role in synaptic transmission. Here, they show the crystal structure of the α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)-sensitive, homotetrameric, rat GluA2 receptor at 3.6 angstrom resolution in complex with a competitive antagonist. The work, says a related News and Views story, offers "those working on signaling in the nervous system, and on membrane proteins in general, a pair of glasses."

As reported in a story at GenomeWeb Daily News, a team led by researchers at the Beijing Genomics Institute has mapped the human "pan-genome" using short next-gen sequencing reads. By integrating the de novo assembly of an Asian and an African genome with the NCBI reference human genome, they found 5 Mb of novel sequences not present in either of the previous assemblies and estimate that a complete human pan-genome would contain between 19 and 40 million bases of new sequence. Their work appears in the advanced online publication of Nature Biotechnology this week.