Since each of the four bases has an equal 1 in 4 chance of occurring at each site along the spine of the DNA molecule, biologists can calculate the probability, and thus the Shannon information, or what is technically known as the “information-carrying capacity,” of any particular sequence n bases long. For instance, any particular sequence three bases long has a probability of 1 chance in 4 × 4 × 4, or 1 chance in 64, of occurring—which corresponds to 6 bits of Shannon information.
