Index >> Bacterial Recombination >> Penetration

Penetration - Permanently bound DNA penetrates the bacterium. dsDNA is converted into ssDNA upon entering the pneumococcus cell. According to one hypothesis,one end of dsDNA enters the cell where an endonuclease digests one of the strands, while the other is pulled into the cell. Experiments with radioactive labelIing of donor DNA show that half the radioactivity is in the ssDNA fragments and half  in the degraded portion. In B. subtilis both strands enter the cell, the degradation of one strand being delayed. Penetrating DNA must have a minimum length of about 750 base pairs