DNA Extraction and Analysis: 1.2.2 and 1.2.3 By Emily

What is DNA? DNA’s purpose is to store information. DNA stands for deoxyribonucleic acid It’s made of subunits of nucleotides. It includes: A nitrogenous base Adenine Cytosine Guanine Thymine A sugar And a phosphate DNA’s purpose is to store information.

What does DNA look like? DNA is a double-helix, so it looks like a twisted ladder

Where is DNA? DNA is stored in the nucleus of cells It’s highly twisted and coiled into chromosomes A healthy human has 23 chromosomes There’s approximately 2 meters of DNA per cell

Why Do You Need to Collect DNA? DNA stores information. It’s why you look like you do. Each person’s DNA is unique, so they can use it to identify people and… Use for analysis of forensic evidence Genetic testing Body Identification

Steps of Collecting DNA You have to go through multiple steps to get the DNA from a cell. It must first be purified of proteins and contaminants Collect cells Open cells to get DNA Separate the DNA from proteins and debris Isolate DNA

Collecting DNA Add lysis solution(This solution contains detergent which breaks down the cells membrane and nuclear envelope and a enzyme which cuts apart proteins called histones that DNA wraps around.) to where the sample is Place the tube with the sample and lysis solution in warm water. Add a salt solution. This causes the proteins and contaminants to clump together. Put the tube into a centrifuge. The proteins and contaminants will sink to the bottom while DNA is still dispersed through the liquid. Remove the liquid and put it into a new tube. Add isopropyl alcohol to the tube and shake gently. The DNA should clump. And you’ll be able to see it.

Analyzing DNA To look at someone’s DNA profile, you need to look at a their Restriction Fragment Length Polymorphisms(or RLFPs). RLFPs are created when an enzyme cuts a specific DNA location. These enzymes are called restriction enzymes. (Example: Haell cuts between base pairs GG|CC.) Different length RLFPs travel through an agarose gel at different speeds in a process known as gel electrophoresis. It creates the pattern known as a DNA fingerprint or profile. Large amounts of DNA are required for analyzing DNA so they use a process called Polymerase Chain Reaction(PCR) to make millions of copies.

Gel Electrophoresis Small RFLPs move faster through a gel than lager RFLPs. DNA has a negative charge, so you can get the DNA to move by applying an electric current into the gel. The DNA will move to the positive end. You can stain the gel to see the groups of DNA with the naked eye.

Online Labs DNA extraction- http://learn.genetics.utah.edu/content/labs/extraction/ Gel Electrophoresis- http://learn.genetics.utah.edu/content/labs/gel/