Genetic Variation in Sordaria Finicola
The purpose of the Sordaria Lab was to explore the affects of genetic variation caused by meiosis and to record how sexual reproduction] affects the amount of crossing over in certain strains of Sordaria Fimicola. These organisms are ascomycetes and are also known as sac fungi. This is because the shape of their asci is in the form of a sac; inside each sac there are structures called ascospores. It is these structures, ascospores, where genetic variation that arises from crossing over is easily seen (Davidson). The organism Sordaria Fimicola is a good example of this process because it is easy to grow on agar plates and because they are easy to be seen when looked at through a…show more content…
Record the two strains that the group is given in your notebook.
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After the agar plate is set up it should look like Figure 3 below. This is an example of the Tan and Wild Type set up. The Gray and Wild type set up will look the same. Figure 3 (Sordaria Genetics…).
After two weeks of incubating, we followed the steps below to examine the Perithecium Squashes (Sordaria Genetics…).
The prepared squashes looked like the figure below when looked at under the microscope.
Figure 4 (Sordaria Genetics…):
Each group member is expected to locate and count twenty asci and record their data in the tables. All the data will be gathered together from all the students in the course. This data will then be used to calculate the cross over frequencies between the two types. This can be calculated by using the formula Type B or C/Total number of asci. Then the frequency of recombination will be calculated from the data using the formula ((Type B+ Type C)/total number of asci). And finally the map distance will be calculated for both the tan spore and the gray spore by using the formula (Percent Cross over/2).
Table 1: Combined Course Data (Tan Spore Color)
Number of Type A Asci (4:4) | Number of Type B Asci (2:4:2) | Number of Type C Asci (2:2:2:2) | Total Number of Asci | 5669 | 4301 | 3976 | 13946 |