Abstract
Mold have been classified and determined according to morphological feature. From the morphological characteristics, an isolate is given species name. Many researchers have engaged in studying an important genus in society, and consequently there will have many eyes for observation. They describe the morphological differences of the isolate finely. From this reason, the social important genus of mold may include many species such as genus Aspergillus, Penicillium, and Fusarium. If the morphological character of the isolate to determine is genetically stable, there will be no problem. But, when the character to determine species is unstable and easy to change depending on environmental condition or growth phase, identification of an isolate often become confused. On the other hand, in the classification by base gene analysis, the number of bases exchange in the gene become great as the number of the base analyzed, and then, difference of the base arrangement also increase. Although it is useful DNA type to classify and identify species, it is a problem how you decide a target gene. If there is a molecular clock to reflect the process of evolution, gene analysis can be considered as an index for classification and identification. We have analyzed the mitochondrial cytochrme b gene of the pathogenic fungi and its related species, and found this gene is useful as an evolution clock.
