Mutation Rate Simulation by Dice Roll: Practice with the Drake Equation

Abstract

Spontaneous mutation, or random genetic change during normal organism function, and random mutagenesis are widely employed by biologists to investigate cell function. The mutation rate of any genetic locus is commonly defined as the probability of mutation μ = M/N. That is, the number of mutations is assumed to be equal to the number of mutant organisms M following N cell division events to produce a population size of N + 1 cells. Measuring the rate of mutant organism production is technically cumbersome due to the need to quantify both mutant and total cell numbers from multiple independent cultures; such measurements are often not feasible for the undergraduate biology laboratory. We present here a simple classroom probability exercise that simulates the production of mutant organisms and measures mutation rate using the Drake equation. This exercise and data analysis may be completed in one hour’s time and without microbial cultivation.