Abstract: Meiotic recombination involves repair of double strand DNA breaks by homologous recombination to form crossovers and noncrossovers. Current models suggest that different mechanisms form these two products: noncrossovers by synthesis-dependent strand annealing; COs by double Holliday junction formation and resolution. In testing these predictions, we found evidence for remarkable dynamism during meiotic DSB repair. This includes switching between repair templates and strand invasion by both DSB ends during both noncrossover and crossover recombination, and extensive branch migration by the Holliday junction intermediates that are CO precursors. I will discuss the mechanistic and regulatory implications of these findings.
Dr. Michael Lichten, now Scientist Emeritus, was a research microbiologist in the Microbial Genetics and Biochemistry Section of this laboratory. He received a Ph.D. in 1982 from M.I.T. with Maurice S. Fox and postdoctoral training at Brandeis University with Dr. James E. Haber. He joined the NCI as a Senior Staff Fellow in 1987, became a Senior Investigator in 1995, and became a member of the Senior Biomedical Research Service in 2000. He retired from government service in 2022, but remains an active member of LBMB as a volunteer researcher. He serves on the editorial board of PLOS Genetics and Biochemical and Biophysical Research Communications. He was elected to the American Academy of Arts and Sciences (2016) and the National Academy of Sciences (2022).