Antibiotics don't create resistance; they kill vulnerable microbes and leave resistant ones to multiply. Every dose is a selection event. Drag the slider to see how antibiotic pressure shifts the population toward resistant strains.
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Vertical gene transfer is the inheritance of resistance from parent to offspring during cell division. Once a bacterium survives antibiotic exposure, it passes resistance genes to all descendants. This is classic Darwinian selection: resistant microbes reproduce, susceptible ones die. Over successive generations, the resistant lineage dominates the population. Vertical transfer alone can shift a community toward resistance in days under sustained antibiotic pressure.
Resistance is selected for, not created — antibiotics don't cause mutations; they kill off vulnerable microbes and let the naturally resistant survivors take over the population.