Chapter 20: Useful Materials

I thought this video showed a cute way in describing the process of gene cloning, which refers to procedures that lead to the formation of many copies of a particular gene. The video goes through gene cloning step by step.

• Step 1: Obtain a plasmid vector and a DNA fragment: these are your starting materials.
• Step 2: Both the vector and DNA are treated with restriction enzymes that cleave double-stranded DNA molecules produced in over-hanging single-stranded nucleotide tails.
• Step 3: The chromosomal and vector DNA are cut into pieces and linked together; the linkage is catalyzed by DNA ligase.
• Step 4: In order to make multiple copies of this molecule the ligation mix is introduced to E. coli cells during the process of transformation
• Step 5: According to the video, the mixture should be placed on ice and then be exposed to 42 degrees celsius to cause a change in temperature.
• Step 6: The cells are then placed on a plate with growth medium. Only the cells that have required the plasmid resistance for the antibiotic can grow in this type of medium.
• Step 7: The plate should be incubated overnight at 37 degrees celsius.

After all these steps, the results should be that each transformed cell produces a colony of cells. Yay we have now gone through the key steps for molecular cloning!

P.S. Didn't you love the guys accent? ...I sure did. :{)

This video explains how scientists obtain a genetic fingerprint at Guy's Hospital in London, England. It shows how a researcher is using an automatic DNA extractor to produce a high purity DNA fragment from a blood sample. Basically, the rest of the video explains how these researchers use gel electrophoresis to produce the needed genetic fingerprint. Why might this be important, you may ask? To answer that question, DNA fingerprinting has gained acceptance as a precise method of identification. Also it is commonly used in forensics by helping provide evidence in a criminal case. Therefore, DNA fingerprinting can be very helpful during these times of identity theft, terrorism, and the TV criminology craze.