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United States Department of Agriculture

Agricultural Research Service


item Peterson, Stephen - Steve

Submitted to: Culture Collections International Congress
Publication Type: Abstract Only
Publication Acceptance Date: 8/29/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Identification of fungal cultures by means of colony appearance and microscopic morphology (the traditional method) is a slow process whose accuracy is largely dependent on the experience of the microbiologist performing the identification. It is known that colony color is an easily mutable character, and micromorphology is also subject to variation based upon the temperature of growth, presence or absence of light, and the exact formulation of nutrients in the growth medium. Such changes would change the identification of the fungus. Molecular genetic characters, such as DNA sequences, are not subject to variation based on temperature or medium composition, and mutation of the sequence is infrequent. Nucleotide sequences from ribosomal DNA have been determined and species-specific nucleotide sequences have been found among species of Aspergillus, Penicillium, and Eupenicillium. Identification of species-specific nucleotide sequences is a rapid method for species identification that does not require the microbiologist to have extensive experience with the fungi, but rather requires ability to correctly perform chemical reactions necessary for sequence analysis. The molecular genetic definition of species (species concepts) stabilizes taxonomy by applying objective, measurable boundaries to species (nuclear DNA complementarity, DNA sequence variation) rather than relying on mutable features. Methods for identifying species-specific sequences are discussed.

Last Modified: 05/26/2017
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