Sordaria fimicola
Sordaria fimicola
"Sordaria fimicola" is a species of microscopic fungus. It is commonly found in the feces of herbivores. "Sordaria 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 "Neurospora and Podospora", is a member of the large class Sordariomycetes, or flask-fungi. The natural habitat of the three species of "Sordaria" that have been the principal subjects in genetic studies is dung of herbivorous animals. The species "S. fimicola" is common and worldwide in distribution. The species of "Sordaria" are similar morphologically, producing black perithecia containing asci with eight dark ascospores in a linear arrangement. These species share a number of characteristics that are advantageous for 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 induced and readily obtainable with particular ascospore color mutants. These visual mutants aid in tetrad analysis, 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 biology 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. Sordaria 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 fruit bodies, called perithecia. An interesting feature of "S. fimicola" is that its fruit 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.
The most common form of "S. fimicola" is a dark brown. Certain mutants are grey or tan. A common experiment for an introductory biology 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. Sordaria 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 fruit bodies, called perithecia. An interesting feature of "S. fimicola" is that its fruit 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.
