Manipulating GenesGenetic Engineering: You can repair genes, insert genes, excise genes or replace genes with gene therapy
Manipulating DNA You can identify who was at a crime scene, a John Doe, paternity of children sequence DNA and more with DNA Technology
What will we do?We are going to identify who was at the crime scene of a vicious murder of Spongebob Squarepants
How do we figure out Who was at the crime scene?
Small amounts of trace evidence will be collected
In this case, body fluid was found near the body and collected
PCR Polymerase chain reaction Sometimes only tiny
amounts of evidence are found
PCR is like a photocopy machine for DNA, so lots of copies are made
What now? The DNA is cut into tiny pieces by
chemical scissors known as restriction enzymes (RE)
Each enzyme cuts at a specific sequence
Each person’s DNA is different, so each RE cuts everybody’s DNA into different numbers and sizes
Gene InsertionMatch the overlapping ends with the appropriate bp and you can insert any gene you want!!!
WHAT NOW? Because everybody’s DNA is different, determining the sizes of each fragment is as good as a fingerprint!!!
How Do We Determine the size of the fragments?
Gel Electrophoresis separates the DNA according to size from biggest to smallest with the use of electricity!!!
What the heck is gel electrophoresis?
DNA is negatively chargedGel electrophoresis takes advantage of that property.
We will actually apply an electric current to the DNA
AGAROSE A semisolid material that has many purposes in science.
It is comparable to a sponge (little holes and big holes)
Fragment size and agarose
Because agar has holes similarly sized fragments will get stuck at about the same places in the agar.
This allows us to actually see bands of DNA in the agar
Fragment size and agarose
If you have big pieces of DNA and little pieces of DNA which do you think would travel the fastest through the agarose?
The smaller pieces!!!
What did you do well on this lab?How could you improve your skills and how
could you reduce the time it took to set up the lab?
Ladder/Standard/MarkerIf we measure how far each set of fragments moved, we can graph the distance (in mm) VS the known fragment sizes (in base pairs) and use this as a kind of molecular ruler
Graph the DNA size standard
(AKA “standard marker”) distances
VSthe given size of the fragments in each band from
your table