Rob Phillips, Fred and Nancy Morris Professor of Biophysics and Biology, and colleagues have measured the rate of DNA transfer from viruses to bacteria. They wanted to find out whether pressure plays a dominant role in transferring the DNA. Instead, he says, "What we discovered is that the thing that mattered most was not the pressure in the bacteriophage, but how much DNA was in the bacterial cell." When the bacteriophages try to inject their DNA into the cells, the factor that limits the rate of transfer is how jam-packed those cells are. "In this case," Phillips says, "it had more to do with the recipient, and less to do with the pressure that had built up inside the phage." [Caltech Press Release]
