They are not limited to passing on their genes in the controlled, linear fashion that all multicellular organisms do. It’s much more of a free-for-all with the microbes. A random sequence of DNA can float into a neighboring bacterial cell and be immediately enlisted in some crucial new function. We’re so accustomed to the vertical transmission of DNA from parent to child that the whole idea of borrowing small bits of code seems preposterous, but that is simply the bias of our eukaryotic existence.
