Shuffling the yeast genome using CRISPR/Cas9-generated DSBs that target the transposable Ty1 elements

• DOI: 10.1371/journal.pgen.1010590
• Publication Date: 2023-01-26T18:26:51Z
• Authors: Lei Qi; Yang Sui; Xing-Xing Tang; Ryan J. McGinty; Xiao-Zhuan Liang; Margaret Dominska; Ke Zhang; Sergei M. Mirkin; Dao-Qiong Zheng; Thomas D. Petes
• Keywords: Retrotransposon; Mitotic crossover; Ectopic recombination; Non-allelic homologous recombination

Although homologous recombination between transposable elements can drive genomic evolution in yeast by facilitating chromosomal rearrangements, the details of underlying mechanisms are not fully clarified. In genome Saccharomyces cerevisiae, most common class transposon is retrotransposon Ty1. Here, we explored how Cas9-induced double-strand breaks (DSBs) directed to Ty1 produce alterations this species. Following Cas9 induction, observed a significant elevation chromosome rearrangements such as deletions, duplications and translocations. addition, found elevated rates mitotic recombination, resulting loss heterozygosity. Using Southern analysis coupled with short- long-read DNA sequencing, revealed important features induced retrotransposons. Almost all reflect repair DSBs at non-allelic recombination; clustered Ty were hotspots for rearrangements. contrast, large proportion (about three-fourths) allelic events have breakpoints unique sequences. Our suggests that some latter extensive processing broken ends produced element extend into sequences break-induced replication. Finally, haploid diploid strain different preferences pathways used double-stranded breaks. findings demonstrate importance lesions retrotransposons driving evolution.