Detection of hidden mitotic crossovers by long-read DNA sequencing

• 成果类型: Article
• 署名作者: Qi, Lei; Zhang, Ke; Zheng, Dao-Qiong; Petes, Thomas D.
• 署名单位: Duke University; Zhejiang University; Zhejiang University
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.2615875123
• 发表日期: 2026-09-01
• 页码: e2615875123
• 关键词: mitotic recombination; yeast; DNA damage repair; LOH; GENE CONVERSION EVENTS; genome-wide analysis; saccharomyces-cerevisiae; RECOMBINANT CHROMATIDS; INDUCED MUTAGENESIS; crossing-over; YEAST-CELLS; gamma-rays; segregation; heterozygosity

摘要

Mitotic crossovers in diploid organisms are usually detected by looking for loss of heterozygosity (LOH) for a marker. Assuming the crossover occurs between two duplicated chromatids, a single reciprocal crossover will result in two recombinant chromatids and two nonrecombinant chromatids. LOH will only be observed when a recombinant chromatid cosegregates with a nonrecombinant chromatid. Cells containing both recombinant chromosomes will not result in LOH. Below, we use long-range DNA sequencing to detect crossovers that do not produce LOH, the hidden crossovers. In wild-type diploids of Saccharomyces cerevisiae, these crossovers occur at a rate of about 4 & times; 10-4/cell division. Long-range sequencing also allows the detection of gene conversions associated with crossovers in samples derived from a single cell. Last, we showed that hydrogen peroxide treatment of G1-arrested cells not only induces frequent recombination, but also a high proportion of two-strand mutation events in which both DNA strands are mutated at the same position prior to replication.