One  of  the  two  strands of the invading DNA molecule is digested by
   nucleases, The surviving DNA strand aligns with a complementary region
   of  the bacterial chromosome and replaces it, producing a heteroduplex
   region where the two strands of DNA are not perfectly complementary.

   Following  DNA  replication  and  cell division, one cell contains the
   original DNA sequence, while the other has been transformed to possess
   the foreign gene.

   This process can be used to establish "linkage", since bacterial genes
   that  are  close together have a high probability of cotransformation,
   and relative mapping distances between linked genes can be determined.