Home • Neurospora crassa FGSC2489 74-OR23-1VA (aka "74A") v3.0
Photo of Neurospora crassa FGSC2489 74-OR23-1VA (aka "74A")  v3.0
This image shows a rosette of maturing asci (meiotic cells) of Neurospora crassa, from Wild type x histone H1-GFP. Histone H1 being a chromosomal protein, the GFP-tagged nuclei (two per spore at this stage) glow in four of the eight ascospores of each ascus; the remaining four ascospores carry the untagged nuclei from the wild-type parent. Photo credit: Namboori B. Raju, Stanford University.

Neurospora crassa is a filamentous fungus, i.e. growing as hyphae rather than forming unicellular yeast cells. Filamentous fungi are important in natural environments as degraders of plant and animal biomass, as pathogens of plants and animals, and as producers of natural products that are used as pharmaceuticals. The genus Neurospora holds a central position in the history of genetics, biochemistry, and molecular biology, as one of the earliest convenient model organisms that helped to decipher the gene to protein relationships of metabolism and gene regulation. Ongoing studies on light regulation, the circadian clock, chromatin and epigenetics, gene regulation, and metabolism continue to yield insights into general eukaryotic biology.

Neurospora crassa strain FGSC2489, often abbreviated “74A” is the most widely used “wild-type” strain in the research community, and it serves as the reference genome for all N. crassa  strains. The current version of the genome is almost complete, for all seven chromosomes from telomere to telomere. The ~42 Mb genome encodes ~10,000 protein-coding genes - more than twice as many as in the fission yeast Schizosaccharomyces pombe and ~25% fewer than in the fruitfly Drosophila melanogaster. An earlier version of this genome, sequenced at the Broad institute of MIT, is available at https://mycocosm.jgi.doe.gov/Neucr2, and was published in 2003 (1).

This genome is closely related to that of Neurospora crassa strain FGSC4200 ORS-SL6a, often abbreviated “ORS6a”. FGSC4200 is closely related to the reference strain OR74A. Strain 74-ORS-6a was obtained by six backcrosses to 74-OR23-1VA (2). FGSC2489 and FGSC4200 are the best matched, near-isogenic reference strains of opposing mating types, matA and mata, respectively.


  1. Galagan JE, Calvo SE, Borkovich KA, Selker EU, Read ND, Jaffe D, FitzHugh W, Ma LJ, Smirnov S, Purcell S, Rehman B, Elkins T, Engels R, Wang S, Nielsen CB, Butler J, Endrizzi M, Qui D, Ianakiev P, Bell-Pedersen D, Nelson MA, Werner-Washburne M, Selitrennikoff CP, Kinsey JA, Braun EL, Zelter A, Schulte U, Kothe GO, Jedd G, Mewes W, Staben C, Marcotte E, Greenberg D, Roy A, Foley K, Naylor J, Stange-Thomann N, Barrett R, Gnerre S, Kamal M, Kamvysselis M, Mauceli E, Bielke C, Rudd S, Frishman D, Krystofova S, Rasmussen C, Metzenberg RL, Perkins DD, Kroken S, Cogoni C, Macino G, Catcheside D, Li W, Pratt RJ, Osmani SA, DeSouza CP, Glass L, Orbach MJ, Berglund JA, Voelker R, Yarden O, Plamann M, Seiler S, Dunlap J, Radford A, Aramayo R, Natvig DO, Alex LA, Mannhaupt G, Ebbole DJ, Freitag M, Paulsen I, Sachs MS, Lander ES, Nusbaum C, Birren B. The genome sequence of the filamentous fungus Neurospora crassa. Nature. 2003 Apr 24;422(6934):859-68. doi: 10.1038/nature01554.
  2. Käfer E. 1982.  Backcrossed mutant strains which produce consistent map distances and little interference. Neurospora Newsl. 29:41-44.
  3. Freitag M, Hickey PC, Raju NB, Selker EU, Read ND. GFP as a tool to analyze the organization, dynamics and function of nuclei and microtubules in Neurospora crassa. Fungal Genet Biol. 2004 Oct;41(10):897-910. doi: 10.1016/j.fgb.2004.06.008.