Question: In a series of experiments, scientists used smooth or rough strains of bacteria. They discovered that one strain was able to pass on its DNA to the other strain, a process called 'transformation'. Which strain was 'virulent' and caused transformation to occur? Question - In a series of experiments, scientists used smooth or rough strains of bacteria. They discovered that one strain was able to pass on its DNA to the other strain, a process called 'transformation'. Which strain was 'virulent' and caused transformation to occur? Smooth rough. Need Assignment Help?