A study led by the Broad Institute and Dana-Farber Cancer Institute revealed that CRISPR-Cas9 gene editing guide RNAs have varied efficiency depending on the ancestry of the cancer cell lines, with higher off-target rates in lines of African ancestry. The research highlights the potential for ancestry bias to cause misidentification of cancer dependencies, crucial for drug target discoveries. Findings published in Nature Communications underscore the need for design considerations in guide RNA development to mitigate bias and improve precision in genomic editing.