It's well understood that populations of species don't distribute at random. Rather, as populations grow, individuals are organized around barriers in the landscape. This organization can be seen in, for example, the growth of the cells around the outer layer of plants and how bacteria arrange themselves in microspores in soil. In both these cases, barriers impact the underlying genetic diversity of the populations. These dynamics have been well researched in larger species—from the way plants disperse to how barnacles spread across a rock, but they have not before been thoroughly studied in smaller systems, like that of bacteria.