''Sordaria fimicola'' is a species of
microscopic
The microscopic scale () is the scale of objects and events smaller than those that can easily be seen by the naked eye, requiring a lens or microscope to see them clearly. In physics, the microscopic scale is sometimes regarded as the scale betwe ...
fungus
A fungus (: fungi , , , or ; or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified as one ...
. It is commonly found in the
feces
Feces (also known as faeces American and British English spelling differences#ae and oe, or fæces; : faex) are the solid or semi-solid remains of food that was not digested in the small intestine, and has been broken down by bacteria in the ...
of
herbivore
A herbivore is an animal anatomically and physiologically evolved to feed on plants, especially upon vascular tissues such as foliage, fruits or seeds, as the main component of its diet. These more broadly also encompass animals that eat ...
s. ''Sordaria fimicola'' is often used in introductory
biology
Biology is the scientific study of life and living organisms. It is a broad natural science that encompasses a wide range of fields and unifying principles that explain the structure, function, growth, History of life, origin, evolution, and ...
and
mycology
Mycology is the branch of biology concerned with the study of fungus, fungi, including their Taxonomy (biology), taxonomy, genetics, biochemistry, biochemical properties, and ethnomycology, use by humans. Fungi can be a source of tinder, Edible ...
labs because it is easy to grow on nutrient
agar
Agar ( or ), or agar-agar, is a jelly-like substance consisting of polysaccharides obtained from the cell walls of some species of red algae, primarily from " ogonori" and " tengusa". As found in nature, agar is a mixture of two components, t ...
in dish cultures. The genus ''Sordaria'', closely related to ''
Neurospora
''Neurospora'' is a genus of Ascomycete fungi. The genus name, meaning "nerve spore" refers to the characteristic striations on the spores that resemble axons.
The best known species in this genus is '' Neurospora crassa'', a common model organ ...
'' and ''
Podospora
''Podospora'' is a genus of fungi in the family Podosporaceae. Fossils of ''Podospora'' have been reported from 12 million year old rocks from central England.
Species
*'' Podospora adelura''
*'' Podospora alexandri''
*'' Podospora ampullacea ...
'', is a member of the large class
Sordariomycetes
Sordariomycetes is a class of fungi in the subdivision Pezizomycotina (Ascomycota). It is the second-largest class of Ascomycota, with a worldwide distribution that mostly accommodates terrestrial based taxa, although several can also be found in ...
, 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
ascospore
In fungi, an ascospore is the sexual spore formed inside an ascus—the sac-like cell that defines the division Ascomycota, the largest and most diverse Division (botany), division of fungi. After two parental cell nucleus, nuclei fuse, the ascu ...
s 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
Ploidy () is the number of complete sets of chromosomes in a cell (biology), cell, and hence the number of possible alleles for Autosome, autosomal and Pseudoautosomal region, pseudoautosomal genes. Here ''sets of chromosomes'' refers to the num ...
organism. The eight ascospores are produced inside an
ascus
An ascus (; : asci) is the sexual spore-bearing cell produced in ascomycete fungi. Each ascus usually contains eight ascospores (or octad), produced by meiosis followed, in most species, by a mitotic cell division. However, asci in some gen ...
. ''Sordaria'' squashes can give us information about crossing over during meiosis. If no crossing over occurs a 4:4 pattern is produced: four black spores, and four 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
Meiosis () is a special type of cell division of germ cells in sexually-reproducing organisms that produces the gametes, the sperm or egg cells. It involves two rounds of division that ultimately result in four cells, each with only one c ...
and
mitosis
Mitosis () is a part of the cell cycle in eukaryote, eukaryotic cells in which replicated chromosomes are separated into two new Cell nucleus, nuclei. Cell division by mitosis is an equational division which gives rise to genetically identic ...
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
spore
In biology, a spore is a unit of sexual reproduction, sexual (in fungi) or asexual reproduction that may be adapted for biological dispersal, dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores fo ...
s are shot towards the light.
Taxonomy
Research to update Sordariomycete fungal taxonomy is ongoing, and the position of ''Sordaria fimicola'' within the taxonomy of the Sordariomycetes is being researched and updated. The sordariomycetes are known as the flask fungi because they are characterized by flask-shaped perithecia and unitunicate asci. Phylogenetic studies of partial 18s ribosomal DNA strands has illuminated the phylogeny of the Sordariomycetes.
Morphological features that characterize the Sordariaceae include the differentiation of the hyphal envelope that surrounds the