Sordaria fimicola

Taxobox
name = "Sordaria fimicola"
regnum = Fungi
phylum = Ascomycota
classis = Ascomycetes
ordo = Sphaeriales
familia = Sordariaceae
genus = "Sordaria"
species = "S. fimicola"
binomial = "Sordaria fimicola"
binomial_authority = (Roberge ex Desm.) Ces. & De Not.

"Sordaria fimicola" is a species of microscopic fungus. It is commonly found in the feces of herbivores. "S. fimicola" is often used in introductory biology and mycology labs because it is easy to grow on nutrient agar in dish cultures. The genus Sordaria, closely related to Neurosporaand Podospora, is a member of the numerous class Pyrenomycetes or flask-fungi. The natural habitat ofthe three species of Sordaria that have been the principal subjects in genetic studies is dung ofherbivorous animals. The species S. fimicola is common and worldwide in distribution. The speciesof Sordaria are similar morphologically, producing black perithecia containing asci with eight darkascospores in a linear arrangement. These species share a number of characteristics that are advantageousfor genetic studies. They all have a short life cycle, usually 7-12 days, and are easily grown in culture. Most species are self-fertile and each strain is isogenic. All kinds of mutants are easily inducedand readily obtainable with particular ascospore color mutants. These visual mutants aid in tetradanalysis, especially in analysis of intragenic recombination.

The most common form of "S. fimicola" is a dark brown. Certain mutants are grey or tan. A common experiment for an introductory lab class is to cross one of the mutant types with a wild type and observe the ratio of coloring in the offspring. This experiment illustrates the concepts of genetic inheritance in a haploid organism. The eight ascospores are produced inside an ascus. Soradia squashes can give us information about crossing over during meiosis. If no crossing over then there is a 4:4 pattern. 4 black spores, and 4 tan spores all lined up. If crossing over does occur there is a 2:2:2:2 pattern visible, or a 2:4:2 pattern.

Another common lab use is to observe meiosis and mitosis in the fruiting bodies, called perithecia. An interesting feature of "S. fimicola" is that its fruiting body is phototrophic. Thus, as it grows the stalk will bend toward a light source and when the sac bursts, the spores are shot towards the light.

This species is officially used by the college board for AP Lab 3: Mitosis and Meiosis for the Advanced Palacement (AP) class AP Biology for high schools to earn college credit. It is specifically used in Exercise: 3B.2.