Figure 17.3: Observation of DNA stained with EtBr in a UV chamber.

Laboratory Experiments related to the Horizontal Agarose Gel Electrophoresis: Horizontal gel electrophoresis is used to answer several biological, molecular biology and cell biology question. Here, in today's lecture we will discuss few selected example of experimental approaches of horizontal gel electrophoresis-

Lab Experiment 17.1 : Analyze the given DNA sample and determine the molecular weight using horizontal gel electrohpresis.

Background Information: The size of a DNA can be determined by comparing the size of the known DNA molecules. The DNA of known sizes are resolved on 0.8% agarose along with the unknown sample. Calculation of molecular weight of the unknown DNA sample is a 5 step process:

1. Resolve the DNA on the Agarose Gel along with the DNA molercular weight markers.

2. Calculate the relative mobility (Rf) using the following formula:

Rf=……………………………………………

3. Plot log molecular mass (y-axis) versus relative mobility (x-axis) of the standards.

4. Perform a linear regression using a calculator or using regression software such as Microsoft Excel.

5. Use the linear regression equation (y=mx+c) to estimate the mass of the unknown DNA.
Log Molecular Weight=(slope)(mobility of the unknown)+Yintercept