Neurospora crassa
Image Credit: Kevin Mc Cluskey

The ascomycete fungus Neurospora crassa is important as a model system for the role filamentous fungi can play in biomass deconstruction, environmental nutrient cycling, pathogenic interactions. During the early years of genetic  inquiry it was used in pioneering investigations of the nature of the gene leading to the description of the one-gene, one-enzyme hypothesis in 1941 (Beadle and Tatum 1941).

In Neurospora, a variety of analyses of tryptophan mutants demonstrated the location of the trp-3 (Tryptophan Synthetase, EC# 4.2.1.20, NCU08409) locus on linkage group II. Because of the relative facility of generating and identifying mutants at this locus, intragenic recombination was used to characterize the relationship among different alleles of trp-3 and these studies showed that a gene was "composed of a larger number of elementary units, arranged in a linear sequence." (Kaplan et al. 1964).

The strain Neurospora crassa FGSC 73, trp-3; mat-a has been subject to whole genome sequencing as part of a retrospective study into the nature of the underlying mutations,  the accuracy of classical genetic mapping,  and as an example of a "small a mating type” genome.  The strain was deposited into the FGSC collection in July 1960 and has been distributed to FGSC clients 50 times.  Data from an FGSC client suggests that it may contain a chromosomal abnormality.

References:

• Beadle, G. and E. Tatum. 1941. Genetic control of biochemical reactions in Neurospora. Proc. Nat. Acad. Sci. 27: 499-506. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.308
• Kaplan, S. , Y. Suyama, and D. M. Bonner. 1964. Fine structure analysis at the td locus of Neurospora crassa. Genetics 49:145-158.