Details of Research Outputs

One of the most prominent forms of shuffling genetic material is homologous recombination. Sexual reproduction, meiosis, is a hallmark of eukaryotic life on earth and is accompanied by homologous recombination of chromosomes which maximizes diversification while minimizing DNA damage. Different mechanisms have been proposed to explain how double stranded DNA (dsDNA) homologues find each other and lock together with their sequences matched so that crossovers between chromosomes result in new chromosomes; Monday, March 2, 2009 345a however, the processes underlying this important feature of meiosis are not yet understood. In this work, we show that even in the absence of proteins or additional polymers, individual dsDNA molecules of 5 kb or longer in solutions containing only monovalent ions, can self-assemble into sequence dependent pairs, where this homologous dependent pairing can occur at lower dsDNA concentrations than those typically found in vivo. We have used magnetic tweezers to probe the stability of these molecular pairs and demonstrate that at room temperature they remain bound for shear forces up to 10 pN. To elucidate the mechanisms that underlie the observed homologous association of pairs, we studied the effect of sequence, dsDNA concentration, non specific competitors, temperature, and salt.