（翻译）Populations of a species that are spread out over a broad geographical range are often arrayed in a cline-a gradual change in one or more characteristics as each population evolves adaptations to its own local environment.
（翻译）Previously, enzymes were prepared mainly from animal organs and plant seeds. However, these sources of enzyme have their limits both in quantity and quality. Microbes, on the contrary, can be cultured at large scale by simple methods. Also, in this case, selective production of certain enzyme in large quantities is possible by adjusting the conditions of culture. Further, microbes have marked adaptability, and mutant species can be induced artificially. Thanks to these advantageous properties, enzymes which cannot be produced from animals and plants can be obtained from microbes.
