In this week's Nature, an international research team reports the genome sequence of Aegilops tauschii, the diploid progenitor of the D genome of hexaploid wheat and a key genetic resource for the crop plant. Using a variety of technologies including ordered-clone genome sequencing, whole-genome shotgun sequencing, and BioNano optical genome mapping, the researchers show that compared to other sequenced and larger plant genomes, the Ae. tauschii genome contains "unprecedented amounts of very similar repeated sequences." The genome also features a greater number of dispersed duplicated genes versus other sequenced genomes and "chromosomes have been structurally evolving an order of magnitude faster than those of other grass genomes," the researchers say.
And in Nature Biotechnology, a Massachusetts Institute of Technology-led group describes a technique for in vivo genome editing using chemically modified Cas9 — the cleaving component of CRISPR that is guided to its target by sgRNA — without the need for a viral delivery construct. The investigators modified sgRNA while maintaining or enhancing its genome-editing activity, and then formulated it in lipid nanoparticles. They show that a single intravenous injection of nanoparticles containing modified sgRNAs and mRNA encoding Cas9 can cut levels of a specific gene in the livers of live mice by around 80 percent. "This strategy may enable non-viral, Cas9-based genome editing in the liver in clinical settings," the researchers say. GenomeWeb has more on this, here.