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the opposite cross, Male B and Female A, we see the opposite results, wherein the largest brood
also has the lowest male ratio at 10.2%. This rati
feminization and possible male killing occurred had it solely male killing, the brood size would
have been significantly smaller. Finally, comparing the homogenous BxB and AxA crosses, the
BxB cross had a higher male percentage than the AxA cross, which insinuates that if they were
otherwise identical, the A individuals had some factor inducing a larger female percentage; also,
looking at the brood sizes for both, it is also clear that there was a significantly reduced brood
size for the AxA cross. Together, both these factors strongly suggest that the AxA cross had
involved male killing, which would induce both effects, and together with the suspected
cytoplasmic incompatibility in the Male A and Female B cross, the data seems to suggest that the
individuals of Strain A are infected with Wolba chi a , while those from Strain B are uninfected.
Looking at the overall combined numbers, the patterns described become even more
clearly visible, with the final evidence coming from the chi-squared analysis. For a difference
between the males and females to be significant that is, for the difference to be due to a certain
cause, and not just due to coincidence the p value obtained from the analysis must be at least
lower than the pre-determined value of R=.05, corresponding to at least a 95% confidence that
this is the case. When one looks at how immensely diminutive the p value is in this case, one
clearly sees that there is absolutely no chance that this difference between males and females was
a fluke indeed, had one originally settled even on a 99% confidence level, and its
corresponding R of .01, as the minimum, the results still would have proven valid. This means
that the former analysis of the identities of the two strains holds true, since the witnessed
differences must have been due to a particular cause, and could not have been fate.
Viewing the results of the gel electrophoresis in Figure 2, it becomes evident that the
positive control and Strain A both have a second line in common in addition to the main line
seen across both DNA-positive controls and strains. The common line correlates to the
mitochondrial marker used to confirm that the DNA used was of quality and that the line ran as it
should have; the second line correlates to the Wolb a chi a gene marker, as shown by its presence
in the positive control, and its absence in the negative control. Thus, its presence in A, but not B,
shows that Strain A is infected, and Strain B is uninfected, confirming the prior analysis....
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This document was uploaded on 03/27/2014 for the course BIO 235 at Rochester.
- Spring '12