In this week's Nature Communications, a team of Chinese researchers presents a genomic analysis of ducks, identifying genes involved in body size and plumage color of the economically important Pekin duck. The investigators compared the genomes of 40 mallards, 36 indigenous-breed ducks, and 30 Pekin ducks, identifying signals of selections. They then bred a population of around 1,000 ducks by intercrossing mallards and Pekin ducks, which they used to pinpoint two genetic mutations in Pekin ducks that are associated with the animals' white down feathers, large size, and feed efficiency. The work provides new insights into "genotype-phenotype associations in animal research and constitutes a promising resource on economically important genes in fowl," the authors write.
And in Nature Biotechnology, a trio of Wellcome Sanger Institute researchers publishes data suggesting that CRISPR-Cas9 genome editing can have greater unintended effects than previously thought. In in vivo and in vitro experiments, the researchers find that CRISPR-Cas9 could not only cause small DNA errors, but significant mutagenesis such as large deletions and more complex genomic rearrangements at target sites. DNA breaks introduced by single-guide RNA/Cas9 frequently resolved into deletions extending over many kilobases, they discover, and genome damage caused by CRISPR-Cas9 at mitotically active cells may have pathogenic consequences. The team stresses the importance of careful monitoring of sequence changes when developing therapies based on the genome-editing technology. GenomeWeb and the Scan have more on this study, here and here.
Meanwhile, in Nature Genetics, a Memorial Sloan Kettering-led team reports the existence of whole-genome doubling (WGD) in nearly 30 percent of roughly 10,000 cancer patients they studied. WGD was found to vary by tumor lineage, in part due to cancer cell proliferation rates, and is associated with increased morbidity across cancer types. The findings indicate that WGD is "highly common in cancer, and is a macro-evolutionary event associated with poor prognosis across cancer types," the scientists conclude. GenomeWeb also covers this, here.