Biofilms are complex microbial communities in which a single species of microorganism can subsist or, commonly, can be polymicrobial, in which a great diversity of bacteria and fungi can be contained. These aggregates consist of a set of microorganisms embedded in a viscous matrix consisting mainly of sugars and proteins. Tests were carried out with the ERIC oligos in order to analyze and know the existing genomic diversity; resulting in only one common ancestor and two generations. It is worth mentioning that the most important characteristics are preserved, including ica genes, but only from the second to the third generation.