In Nature this week, a team from the University of California, San Diego publishes a study demonstrating the feasibility of a gene drive in lab mice. The scientists used CRISPR-Cas9 genome editing to promote the inheritance of an engineered allele of the tyrosinase (Tyr) gene and, while unsuccessful in male rodents, were able to boost the rate of inheritance of the Tyr allele in the female animals to as much as 70 percent. The authors state that further refinement of their technique is needed to increase the frequency of gene conversion in both males and females and reduced the prevalence of drive-resistant alleles before it could be applied to wild populations. However, "the copying efficiencies that we observed here would be more than sufficient for a broad range of laboratory applications," they note. The Scan has more on this, here.
Also in Nature, a group led by scientists from Memorial Sloan Kettering Cancer Center describes the use of circulating tumor DNA in cerebrospinal fluid (CSF) to track the progression of gliomas. The researchers analyzed CSF obtained via lumbar puncture from 85 glioma patients and were able to detect tumor-derived DNA in 42 of them. The ctDNA was associated with both disease burden and adverse outcome, and had a genomic landscape that closely resembles that of tumor biopsies. While not all gliomas release DNA into CSF, the presence of ctDNA in the CSF may be an early indicator of progression in glioma, the researchers say.
And in Nature Communications, a Broad Institute team reports a new CRISPR-based platform for genome editing. Rather than using Cas9 or Cas12a, the system uses Cas12b as its RNA-guided nuclease due to its small size, and the scientists were able to overcome efficacy issues by redesigning the protein to function better at body temperature. The resulting CRISPR system offers greater specificity than CRISPR-Cas9 and represents "a promising tool for in vivo genome editing," the authors conclude. GenomeWeb has more on this, here.