1. What is Semi-Log Graph paper…. And WHY do I need to know?

2. DNA can be cut, using RESTRICTION ENZYMES… into segments of differing lengths.

3. After DNA is separated on an agarose gel by electrophoresis, the migration of fragments of known size can be compared to that of fragments of unknown size.

4. Suppose we have digested DNA from two viruses ~ both with Hind III, And electrophoresed the DNA from both on an agarose gel

5. Electrophoresing the DNA on an agarose gel ~~ causes the migration of the fragments.

6. After running the gel ~ you measure the distance the DNA migrated.

7. Table 1. Restriction enzyme analysis of λ and UPCFV DNA λ Virus U.P. Cabin Fever Virus (UPCFV) DNA Hind III digest DNA Hind III digest Size (kb)Distance (mm) Size Distance (mm) migratedmigrated 23.13 ?5 9.4214 ?12 6.5618.5 ?15 4.3623.5 ?27 2.3232. 2.0334 0.5650

8. In order to determine the sizes of the U.P. Cabin Fever Virus DNA, you will make a standard curve for the known Lamda DNA YUK! This does not show a linear relationship between the fragment size and distance migrated… down towards the right side of the graph, it would be difficult to determine size… Size of fragment Length migrated

9. A logarithmic graph, basically takes an EXPONENTIAL graph and changes it to a LINEAR one … but using funky graph paper & by using the log function. (log function is the inverse of an exponential function) Size of fragment Length migrated

10. When a curve is not straight.. It can be made straight with logarithms. migration Log of fragment length

11. Scientists use logarithmic graph paper to manage large amounts of data easily

12. And when you are talking kilo base pairs…. And DNA…. You are discussing a LARGE amount of data

13. See the funky graph paper? The axis with the logarithmic info runs in cycles… The cycles differ by a factor of 10 btw, this is an example of 6 cycle graph paper

14. See the funky graph paper? One of the virtues of semi- logarithmic plots is their ability to show a very wide range of values.