Mapping the Genes of Sordaria Fimicola

The main purpose of this experiment is to examine the results of wild-type mutant crosses which influence the arrangements of ascospores in asci in the fungus Sordaria fimicola. These resulting arrangements help calculate the map distance between the centromere and spore color genes in Sordaria. My hypothesis was that due to so many group observations accounted in, the data will be underestimated and the results will not fit into the chi square table. A sample from Petri dish with both mutant stock cultures is observed after a week. The ascospores must appear in MII pattern 2:2:2:2 or 2:4:2 arrangements in order for the crossing-over to occur. Next, based on the data collected, the class calculated the map distance. If the map distance does not fit the value obtained by the researchers from the many successful experiment attempted, then the experiment had errors. And due to this, the class experiment cannot accept the null hypothesis according to the chi square test. However, our class experiment accepted the null hypothesis and so it was a success.

Introduction

The fungus Sordaria fimicola is commonly used to study the different processes of cell cycles such as the assortment of genes and the crossing over during meiosis. Considering the importance of genetics in the world today, this experiment is crucially valuable in helping the students gain knowledge in the different processes of cell cycle and learning how to attempt similar experiments on their own in the future. Sordaria fimicola requires “both mitotic and meiotic nuclear divisions to manufacture eight haploid ascospores” (Helm, 1998). This fungus “spend most of its life in haploid condition” (Glase, 1995). When the haploid nuclei fuse together in the cells, they beco...

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... crossover more often is because some regions of chromosomes have a greater, or lesser, tendency to form crossovers than other regions. For example, the centromere seems to inhibit crossing over and genes located close to it do not crossover as much as they should based solely on their physical location. However, because a genetic map is based on crossover frequencies, the relative distances between genes do not correspond to real, physical distances.

Works Cited

Helms, Doris et al. Biology in the Laboratory: Third Edition. New York: W.H.

Freeman and Company, 1998.

Glase, Jon C. A Study of Gene Linkage and Mapping Using Tetrad Analysis in the Fungus Sordaria fimicola. New York: Cornell University, 1995.

http://www.ableweb.org/volumes/vol-16/1-glase.pdf

Mitosis and meiosis. (n.d.). Retrieved from

http://kvhs.nbed.nb.ca/gallant/biology/sordaria.html