The term gene bank refers to any system by which the genetic composition of some population is identified and stored. Many different kinds of gene banks have been established for many different purposes. Perhaps the most numerous gene banks are those that consist of plant seeds, known as germ banks.

The primary purpose for establishing a gene bank is to preserve examples of threatened or endangered species. Each year, untold numbers of plant and animal species become extinct because of natural processes and more commonly, as the result of human activities. Once those species become extinct, their gene pools are lost forever.

Scientists want to retain those gene pools for a number of reasons. For example, agriculture has been undergoing a dramatic revolution in many parts of the world over the past half century. Scientists have been making available to farmers plants that grow larger, yield...