Sordaria Lab Report

2287 words 10 pages
Meiosis and Genetic Diversity in Sordaria
Biology 110 Lab

Introduction: In Israel there exists multiple spots in the mountains called Evolution Canyons, which are all located between a southern facing slope (SFS) and a northern facing slope (NFS). What’s particularly interesting about these locations is that despite the two slopes being on opposite sides of a small canyon, they exhibit extremely contrasting conditions. The SFS receives multiple times the UV radiation from the sun that the NFS receives, has fluctuating weather, and is generally an arid and less hospitable region compared to the temperate, stable environment of the NFS. Scientists collected wild type Sordaria fimicola inhabiting both slopes and discovered
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Table 4 should include the results from all the students in the course, which will be provided by the course coordinator. After recording all the data, the frequency of all recombinant asci, the frequencies of both possible types of recombinant asci, and the ratio of one recombinant asci to the other should be calculated and written in the four data tables.

Figure 2: Mating Plate After Two Weeks of Incubation and Growth (from Steve Holmes)

Figure 3: Perithecium Squash and Observable Asci (from Steve Holmes)

Figure 4: Crossing over versus not, and the results

No crossing over always results in a 4:4 asci pattern, while crossing over in meiosis I can result in different exchanges of genes, including the color gene, which will result in asci with patterns of 2:2:2:2 or 2:4:2 following the splitting of homologous chromosomes in meiosis II and a final mitotic division to create 8 ascospores.

*Note: Steve Holmes’ data
Table 1: Individual Data Non-recombinant | Recombinant | Total # of Asci | Total # Recombinant Asci(B + C) | Frequency of Recombinant Asci(B + C)/total # asci) | Frequency of Type B Asci(B/total # asci) | Frequency of Type C Asci(C/total # asci) | Ratio B/C | # of Type A Asci(4:4) | # of Type B Asci(2:4:2) | # of Type C Asci(2:2:2:2) | | | | | | | Tan Spore Color | | | | | | | | | | | | |