Before revision:  We present an analytical model using a simplified version of the known structure of dsDNA bound to ssDNA/RecA filaments. This model predicts that the mechanical energy stored in dsDNA bound to RecA increases non-linearly with the number of contiguous bound dsDNA triplets. We suggest that the free energy increase for the homology searching state is much more rapid than the increase for the post-strand exchange state and propose that this difference may play a vital role in the homology search/strand exchange process .
After revision:  We present an analytical model for the dsDNA tension. The model suggests that the binding of additional dsDNA base pairs to the DNA/RecA filament alters the tension in the dsDNA that was already bound to the filament. Such coupled tension changes may explain several previously unexplained experimental results .