Answer:
Gene recombination
Step-by-step explanation:
Bacteria have two mechanisms of genetic variability: gene recombination and mutation.
Recombination is the mix of genes between individuals. It can occur in three different ways: conjugation, transformation and transduction.
The transformation process is the simplest. It occurs by incorporating free DNA into the bacterial cell;
Transduction is the transfer of genetic material between cells, mediated by bacteriophages (viruses capable of infecting bacteria);
Conjugation is the process of transferring DNA from one bacterium to another, involving contact between the two cells. This is the most complex and most important process in gene recombination.
The conjugation process begins with the formation of a specific "donor-recipient". Then, preparation for DNA transfer occurs. After this transfer, a replicative plasmid (molecules that carry genetic information from bacteria) is formed at the receptor.
Mutation, in turn, corresponds to inherited changes in the DNA sequence. It is the primary source of variability that works in conjunction with gene recombination.