Filamentous fungal genomes range in size from two to five times that of yeast. Reflecting their increased genetic complexity, filamentous fungi contain more genes than yeasts. Since filamentous fungi constitute 90 percent of all fungi and are the basis of a multi-billion dollar US industry, these novel genes are of tremendous economic importance. Fungi produce an extraordinary number of secondary metabolites including known mycotoxins such as aflatoxin and commercially important antibiotics such as penicillin. Unlike yeast most fungi form distinct asexual spores that constitute the chief means of dispersal of the organism.
Fungi have substantially greater metabolic versatility than yeast.
The potential here for bioremediation is only beginning to be exploited. Generally, once fungi can be cultivated they can be genetically transformed with exogenous DNA in a site-directed fashion, thus paving the way for genetic engineering of one fungus using developmental or metabolic capacities encoded by a different fungus. The determination of complete genomic sequences of filamentous fungi is now an important and readily achievable goal. Initially the DNA sequence itself will be most informative in proportion to extent to which the genome sequenced is already understood genetically. The DNA sequences of these genes will be similar enough in all organisms that the presence of these genes in a raw DNA sequence is identifiable and interpretable.