Double-strand-break Repair, Gene Conversion, and Postdivision Segregation (original) (raw)

1. R. Rothstein
2. Department of Microbiology, UMDNJ-New Jersey Medical School, Newark, New Jersey 07103

Excerpt

After the discovery of plasmid gap repair in yeast (Orr-Weaver et al. 1981), we proposed a general model for genetic recombination based on the repair of double-strand breaks or gaps (Szostak et al. 1983). In Figure 1, we summarize the sequence of events proposed in that model. We postulate that the initiation event of meiotic recombination is a double-strand break that is enlarged to a gap on one of the two chromatids that interact during a gene conversion event. The two free ends invade the homologous regions of one of the two nonsister chromatids and create two Holliday structures on each side of the gap. In the version of the model shown in Figure 1, the ends are shown to invade asymmetrically, which is consistent with most meiotic gene conversion data in fungi. Another version depicts a symmetric invasion with rapid branch migration of the double Holliday structure (Szostak et...

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  ↵* Present address: Department of Human Genetics and Development, Columbia University College of Physicians and Surgeons, 701 W. 168th Street, New York, New York 10032.