Here, we deal with small numbers, very small numbers, in fact, we often deal with single molecules, where the world becomes one of random events and probabilities. This, of course, is reminiscent of our very own experience, where the quality of life is described in mortality rates and life expectancy, risk factors and insurance rates. What really happens in our lives, however, can be completely different from these expectations, in short, our future is fairly unpredictable. With ever increasing sophistication of their tools, biologists are entering this realm of small numbers and complex interactions. It is a world of microscopic properties, where numbers and intensity of interactions among molecules are in constant flux.
Biological systems are truly dynamic systems.
Thanks to modern powerful computers, some of these processes can be simulated, because it is impossible to observe them for lack of sensitive instrumentation. And it is often the instabilities within the instruments themselves that limit the resolution of the observable signals. A gene has been defined as a hereditary entity that cannot be partitioned any further into smaller units. This is a powerful and suggestive idea and without doubt has been shaped by the concurrent developments in particle physics in the early 1900s. The critical question to grasp the importance of the gene is how mutations, the random chemical changes that affect the instructions stored in genes, are selected upon in a population of an organism.