This application requests partial funding for the 2003 and 2005 FASEB summer research conference on Genetic Recombination and Genomic Rearrangements. The 2003 conference will be held July 26-31 at Snowmass village, Colorado and will be the tenth of a highly successful series of bi-annual conferences on genetic recombination. These conferences join investigators studying many diverse aspects of genetic recombination, in a range of biological systems and with different experimental approaches. Presentations will introduce new and unpublished work on timely questions in the field and will encourage discussion from all participants. Eight plenary sessions will involve topics such as recombination mechanisms, properties of prokaryotic and eukaryotic recombination, meiotic processes, the role of recombinational processes in repair of DNA damage, site-specific recombination and transposition, and genomic rearrangements. Forty speakers, among the best experimentalists and thinkers in these particular areas, have agreed to present their most recent and unpublished work. Several timely issues will be discussed including the role of the breast cancer susceptibility gene BRCA2 in the control of recombination, the role of recombination in repair of the replication fork and the cell cycle checkpoint response to DNA damage and its influence on repair and recombination. Characterization of recombination and repair factors known to underlie human syndromes will propensity to cancer will be discussed, using mammalian and other model genetic systems. Approximately 160 other participants will be chosen from among the applicants to the conference. While maintaining rigorous standards of excellence in selecting participants, every attention will be paid to achieving a balanced representation of age, gender, race and geography. All will be encouraged to participate in discussion, workshops and poster sessions. There will be a workshop on a controversial topic, the role of the Mus81 complexes in recombination intermediate processing, and two poster sessions, each lasting two days, will provide an additional forum for presentation of current work. The 2005 will be organized similarly but will feature different speakers. By emphasizing truly exceptional research in a modestly sized conference setting, the FASEB conference provide unique opportunities for the exchange of information, technology and perspective among new and established investigators in the recombination field.