Direct parental (DIPA) CRISPR is a simple and accessible method for insect gene editing where Cas9 ribonucleoproteins are directly injected into adult females. Japanese and Spanish scientists collaborated to develop the new method to successfully establish gene knockouts and knockins in cockroaches and red flour beetles where conventional embryo microinjection cannot be applied. The new method cannot, however, be applied in all insects, including fruit flies.
Although genome editing holds unprecedented promise in the treatment of diseases, one of the major obstacles is that existing technologies frequently result in unwanted mutations or can fail to introduce any changes at all. Now, a new resource called Repair-seq has been developed, and it allows scientists to investigate how the complex cellular DNA repair mechanisms influence the outcome of genome editing technologies.
Scientists at Israel’s Agricultural Research Organization (ARO), Volcani Center in Rishon Lezion, have used CRISPR-Cas9 genome editing tools to introduce indel mutations in a membrane transport protein, slc45a2, to create a new stable strain of tilapia that does not develop suspicious red and black blotches on their skin and instead acquires appealing, uniform, red skins that drive up their market price. These findings demonstrate genome editing is useful for the generation of improved and traceable phenocopies of commercially popular and profitable traits that do not require large-scale genetic manipulations that generate new phenotypes but subtle genetic changes.
Researchers at CRISPR Therapeutics compare three homology-independent off-target assessment methods– GUIDE-seq, CIRCLE-seq and SITE-seq–and infer all three methods are competent means of nominating off-target sites, validating CRISPR-Cas9 as a platform for the development of clinical therapeutics.