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.
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 become a diploid nucleus however the nucleus does not stay in the diploid stage for long. Immediately after, it goes under the process of meiosis where it divides into four haploid nuclei. When these four haploid nuclei divide and replicate mitotically, they form total of eight haploid ascospores. According to the research studies “Sordaria ascospores are generally black however mutation in these genes can cause either tan or gray colored mutant spores” (Glase, 1995). The crossing over of the non-sister chromatids occurs in the first meiosis (Meiosis 1). Meiosis with no crossing over results in M1 pattern of 4:4 arrangements, which contains 4 black spores and 4 tan spores and vice versa. Based on the previous studies and successful researches, my hypothesis is that group finding will result in more cross-over genes than non cross-over, which will lead the class data to fit the general expected value for the map distance of the mutant gene obtained by scientists which is “26 map units” (Helm, 1998).
Two Petri dishes per group with stock culture are kept in the dark for a week. When observed, a week later, there are two possible outcomes that can be obtained by performing this experiment, one is that cross-over might not...