ABSTRACT
Since their discovery in the 17th century, thanks to the invention of the microscope by Van Leeuwenhoek, and until about 25 years ago, bacteria have been considered as individual planctonic cells. For a long time, prokaryotes have represented the exact paradigm of unicellular life and yet they constitute a model of “freedom” in biology that individual cells belonging to a multicellular organism do not possess. Actually, although all of them possess the same genetic potential, individual cells in both animal and plant multicellular organisms are compelled to differentiate in the various tissues and hence only use a limited amount of their overall genetic information.
