Isomerization -A simple steric rearrangement of the parental strands converts the inner (bridging) strands into outer strands and vice versa. This process is called 'isomerization'. A one-strand crossover can be converted into a two-strand, crossover by isomerization or by branch migration. As a result of isomerization the arms flaking the strand crossover are put in a recombinant configuration.
